Surprisingly, no Order Spell has been removed compared to Warriors of the North. Well, sort of. Dragon Slayer has been dumped and replaced with the more general Titan Slayer, but this is more of a buff and reframing of an existing Spell than an actual removal.
One interesting point is that Runic Word is actually in the code as an Order Spell, but it's commented-out, suggesting that they'd long planned to dump Rune Magic as a school but had originally intended to keep Runes as a mechanic, and changed their mind fairly late in development. The other Rune Magic Spells that weren't co-opted are also still in the code, but they've been shunted off to their own section, not commented-out within the other schools, suggesting they were held onto only for just-in-case purposes, rather than with any intent to use them in this game. Indeed, Runic Word even has code for Warlock benefiting it!

Axe of Magic
Crystal Cost: 2 / 5 / 8
Mana Cost: 5 / 12 / 18
Level 1 Statistics: Damage: 100; Axes: 1
Level 2 Statistics: Damage: 200; Axes: 2
Level 3 Statistics: Damage: 300; Axes: 3
Hits a single enemy unit for Physical
damage.
For whatever reason, its Magic Crystal and Mana costs have been somewhat increased past the first level, further ensuring it's not really worth using when you could just use Ghost Blade or Chaos Missiles or any number of other Spells.
I'd recommend you never bother even learning it.

Lightning
Crystal Cost: 7 / 10 / 20
Mana Cost: 15 / 25 / 35
Level 1 Statistics: Strikes one target
Level 2 Statistics: Bounces to additional targets twice
Level 3 Statistics: Bounces to additional targets four times
Hits a single target for 100-200 Magic
damage, with a 15% chance to Shock. Higher Levels of the spell will also 'bounce' to additional targets.
Inexplicably, its damage has been changed to no longer rise with Level. As such, it's now horribly, horribly bad, only vaguely useful at Level 1 if you get it reasonably early and absolutely not worth Leveling at all.
I have no idea why Dark Side made this change. Lightning was always difficult to find good opportunities to use it past the early game; it didn't need to be nerfed. This is just bizarre.

Healing
Crystal Cost: 1 / 2 / 3
Mana Cost: 3 / 2 / 1
Level 1 Statistics: Healing/Damage: 50, Duration Reduction: 1
Level 2 Statistics: Healing/Damage: 150, Duration Reduction: 2
Level 3 Statistics: Healing/Damage: 250; Duration Reduction: Infinite
Targets a single allied organic non-Dark unit or a single enemy Dark unit. Allied Light or Neutral organic units are healed, though dead units cannot be recovered this way, while enemy Dark units take Magic
damage instead. Inorganic units cannot be targeted at all. Reduces the duration of Bleed and Plague when targeted on an ally. Damage is equal to half the healing value.
Switched to a Light/Dark distinction, and no longer binary on purging negative effects. (Though it doesn't affect Poison anymore, either) It also now only uses half its number when doing damage, for whatever reason. The above describes the 'basic' version of the Spell: there's a Quest to upgrade it to a Dark-compatible version. You shouldn't learn Healing directly yourself, as its base version is borderline useless and critically once you've turned in three Healing Scrolls you're taught the Dark Heal Spell without having to burn a Magic Crystal on it.
The Dark version will heal any organic ally or harm any organic aligned enemy. (ie it won't hurt Neutral units or Vikings) Other than this and having a modified animation, it's identical to the regular version.
In practice, its primary use is purging Bleeding to prevent casualties. The nuking capability is more general than in prior games, but it's also much weaker; 50 Magic damage was already worse than Flaming Arrow's 70 Fire damage, but now that it's 25 Magic damage it's just pathetic. Healing has always had a favorable growth factor relative to most damage Spells, gaining twice its base damage instead of roughly its base damage, but where in prior games that meant Level 3 Healing did 250 Magic damage to Undead vs Level 3 Flaming Arrow doing 210 Fire damage, in Dark Side it means doing 125 Magic damage to non-Neutral enemies. Notice that Lightning will roll better than that 75% of the time. (While now being awful, it should be emphasized)
So unless it's vitally important the damage is cheap, Healing just isn't good as a nuke Spell in Dark Side.
The healing, meanwhile, runs into two problems: first of all, it takes until at minimum partway through Monteville to be able to get the Dark version of Heal. Second of all, Dark Side's early game has fairly accelerated Leadership growth in general compared to prior games. The combination of the two means there is a very narrow window in which non-resurrecting healing is particularly valuable. If you take advantage of early-game Red Dragons, you might get some real use out of it, maybe, but overall? Healing is mostly good for purging Bleeding.
Which makes it unfortunate that it merely reduces the duration of Bleeding prior to getting it to Level 3. The Level 1 and 2 versions are nearly useless most of the time.
Oh, and as a bonus it has the all-too-common 'thing that claims to purge Plague doesn't actually do so' issue.
It at least has Defiler boost both its healing and damage?

Resurrection
Crystal Cost: 10 / 15 / 25
Mana Cost: 10 / 20 / 30
Level 1 Statistics: Recovers Health: 200; Target's Level: 1-2
Level 2 Statistics: Recovers Health: 400; Target's Level: 1-3
Level 3 Statistics: Recovers Health: 600; Target's Level: 1-4
Targets a single allied non-Dark organic unit, restoring health to the unit. 'Overflow' healing will resurrect dead members of the unit if it has suffered casualties in the current battle. Can even target corpses, restoring a fallen stack to functionality.
As with Healing, you can get a Dark version of the Spell that works on basically anything (Yes, even Plants) and doesn't demand Crystals for that first level. Otherwise, its mechanics haven't really changed.
Getting the Dark Resurrection Quest done usually takes until you're closing in on the end of the game, unfortunately. As such, where in prior games it was possible to get lucky with an early Resurrection Scroll changing things from quite early on, in Dark Side you basically always end up only getting a hold of it when you're so far into the game it's not so important a utility.
This is further exacerbated by the extremeness of class/character differences; if you're playing Daert, your Intellect will be massive enough for Resurrection to undo shockingly significant casualties, but you won't care because a turn spent undoing casualties is a turn not spent killing things with your mind, and your army is too tiny to really contribute. If you're playing Neoline or to a lesser extent Bagyr, your army will be massive and prone to getting into the thick of things to potentially take casualties, but you won't have the Intellect to properly support Resurrection.
As such, while the raw changes to Resurrection seem like Dark Side should be its best entry in the series, in practice it's probably its worst.

Dispel
Crystal Cost: 1 / 2 / 5
Mana Cost: 5 / 5 / 5
Level 1 Statistics: Removes most effects on a friendly target.
Level 2 Statistics: Removes most effects on a friendly or enemy target.
Level 3 Statistics: Removes most negative effects on a friendly target or all positive effects on an enemy target.
Targets a single unit, removing some portion of effects on the unit. Burn, Freeze, Bleeding, and Poisoning are unaffected.
No longer works on the damage over time effects. Which sucks, since those were the main effects you wanted to be able to Dispel on a consistent basis.
Heroes that use Phantom are also nearly nonexistent in Dark Side, making it much less useful to get to Dispel 2.
It's still useful to have Dispel at times, and it's sufficiently cheap on Magic Crystals it's probably worth leveling whenever you can just in case, but you won't use it nearly as often as in prior games.

Life Light
Crystal Cost: 4 / 8 / 16
Mana Cost: 10 / 10 / 10
Level 1 Statistics: Healing: 40, Bleed Power: 8%, Duration: 2
Level 2 Statistics: Healing: 80, Bleed Power: 16%, Duration: 3
Level 3 Statistics: Healing: 120, Bleed Power: 24%, Duration: 4
A 7-tile circular region becomes affected by a rain of holy light, healing allied units each Round (Including immediately upon casting), while inflicting Bleeding on enemy creatures. Later activations act with an Initiative of 2.
Life Light has been completely overhauled into something far more coherent with the name in the .txt file: Holy Rain. It's cheaper past the first level, lasts multiple turns, heals multiple times, and instead of scaring off Undead it causes enemies to Bleed, which being percentile damage+max Health reduction is amazing. The actual healing is worse up-front than in the previous games, but since it activates multiple times that's misleading, and it's cheaper, and mass-Bleeding is, again, amazing. (Not to mention the healing was never all that useful of an effect by the time you got it in prior games)
It's also been given a Dark counterpart...

Dark Shroud
Crystal Cost: 4 / 8 / 16
Mana Cost: 10 / 10 / 10
Level 1 Statistics: Healing: 40, Bleed Power: 8%, Duration: 2
Level 2 Statistics: Healing: 80, Bleed Power: 16%, Duration: 3
Level 3 Statistics: Healing: 120, Bleed Power: 24%, Duration: 4
A 7-tile circular region becomes affected by a rain of evil stuff, healing allied units each Round (Including immediately upon casting), while inflicting Bleeding on enemy creatures. Later activations act with an Initiative of 2.
... though while the game will insist these two Spells care about the Light/Dark divide, in actuality their animations are the only difference. You might as well pick whichever you prefer the animation for and focus on it.
This is another case where you can turn in three copies of the Light version of the Spell to be taught the Dark version. In this case, the only practical benefits are quest advancement, saving 4 Mana Crystals, and that Dark Shroud advances a Medal while Life Light does not. That's enough to be worth pursuing it, but much less of a payoff than some of these Quest-learnable Spells.
Note that unlike the other four cases of turning in Light Scrolls to learn a Dark Spell, you don't simply upgrade the Light Spell into an omnicompetent version of itself; Dark Shroud is a distinct Spell in its own right, with its own graphic and place in your Spellbook. It's also worth noting that Life Light is considered by the game to be a fairly ridiculously high-value Spell, and as such the Scrolls are rare: it may take a long time to actually get Dark Shroud via Quest, and unlike the other Light-to-Dark-from-Quest Spells, Dark Shroud is very useful the instant you learn it. Given all these factors, it's worth considering learning Dark Shroud manually if you luck into its Scroll early on, instead of trying to save on valuable Magic Crystals at the cost of spending much of the game without Dark Shroud. Particularly since Dark Shroud is one of the better ways to build progress on one of your Medals: the earlier you get started on such Medals, the better.
One caveat on the healing: the game is a bit weird, and if there's multiple injured units being healed by Dark Shroud/Life Light at the same time, the healing will sometimes be no more than the weakest healing being provided. Uninjured units don't 'count', but if you have an Imp stack missing 5 Health sitting next to an Archdemon stack missing 500 Health, you can end up only healing 5 Health on the Archdemons. This is a fairly obnoxious, weird limitation if you're trying to use either Spell primarily as a healing Spell, but honestly they're both far better used to inflict mass Bleeding, with any healing that happens being treated as a bonus, so it's not a big deal, just something to keep in mind when you're considering your moves.
And another example of Dark Side's weird bugginess in action.
I have no idea what causes it to sometimes have this glitch and other times not. I've yet to find the pattern to it.
But that's not too bad, as mass Bleeding is amazing no matter which class/character you're playing as, and most of the time healing a unit is a bonus.
Note that the 'Bleed Power' is relative to the base Bleed strength, meaning that Level 3 Life Light/Dark Shroud at base actually takes the baseline 5-10% damage and reduces it to less than a quarter. Fortunately, this is boosted by Intellect and the Wight Skill; at Rank 3 Wight and 68 Intellect, the Bleed will be just as strong as base Bleed, and then grow stronger from there. Daert will trivially shoot well past 68 Intellect in the mid-to-late-game.
Also note that the duration for Life Light/Dark Shroud's field effect is boosted by the Defiler Skill and standard Intellect-based duration extension. Battles in Dark Side tend to be short enough 4 turns is already plenty, but hey.

Bless
Crystal Cost: 3 / 3 / 10
Mana Cost: 10 / 10 / 20
Level 1 Statistics: Duration: 2 turns
Level 2 Statistics: Duration: 3 turns
Level 3 Statistics: Mass; Duration: 3 turns
Affected units always roll for maximum damage on all attacks. (Melee or ranged) Cannot be applied to Dark or inorganic units.
Bless is now barred from being cast on any Dark units, instead of Undead in specific.
... but it's another Spell you can turn in three copies of its Scroll to be taught a Dark version for free. At that point it can be cast on anything that isn't a droid, Cyclops, or Spell-immune. And yes, it still affects Talents, just like in Warriors of the North.
And it's not at all unusual for you to find 3 Bless Scrolls in a single shop, so you can easily get the Dark Bless done quite early in the game -I've had runs where getting a hold of the guy who kicks off the Quest is what delayed me from getting Dark Bless instead of the need to get three Scrolls.
It's not particularly useful for Daert, but it can be pretty amazing on Neoline, especially since she has strong incentives to use some of the more randomized units in the first place; Blood Priestesses, for example, very much appreciate always getting their high roll.

Titan Slayer
Crystal Cost: 3 / 3 / 25
Mana Cost: 5 / 10 / 25
Level 1 Statistics: Bonus Damage: 20%; Duration: 3 turns
Level 2 Statistics: Bonus Damage: 30%; Duration: 4 turns
Level 3 Statistics: Bonus Damage: 30%, Mass; Duration: 4 turns
Affected units gain bonus damage against Level 5 units.
Dragon Slayer's replacement, which applies to everything Dragon Slayer did and more. Huzzah!
I've personally never used it, but I can imagine a real person doing so, particularly when fighting eg a battlegroup made entirely of Black and Ice Dragons. It's not like you've got many other options in that scenario, after all.
Though unfortunately where Dragon Slayer scaled its boost with Intellect, Titan Slayer does not, so that hurts it. It at least benefits from Warlock, allowing it to reach a maximum boost of +39%.

Magic Armor
Crystal Cost: 8 / 12 / 20
Mana Cost: 15 / 20 / 30
Level 1 Statistics: All Resistances: 20%; Duration: 2 turns
Level 2 Statistics: All Resistances: 25%; Duration: 3 turns
Level 3 Statistics: All Resistances: 30%; Duration: 4 turns
Raises a single allied unit's non-Astral (



) resistances, subtracting the unit's innate resistances from this effect. (This cannot result in Magic Armor's modification being negative) Cannot be applied to Undead.
The name has been changed, presumably because the idea of our Dark heroes being backed by Christian-y divinities seems a bit off, but the mechanics are familiar. It's even barred from being applied to Undead still, unlike a lot of other discriminating Order Spells in Dark Side.
It's worth noting a Quest on Aralan calls for a Magic Armor Scroll. It's... a completely ignorable Quest, but if you're shooting for 100% completion you might consider holding onto a Magic Armor Scroll to make that Quest go faster.
Magic Armor remains held back by its high cost, failure to synergize with innate resistances, and to a lesser extent the continuing inability to apply it to Undead, but Dark Side is by far the most extreme entry in the series about letting the player significantly stack resistances, and its late game fights are often designed in a manner where having a nearly-invincible tank hold enemy attention is extremely high-value. (And may in fact be the only way for you to win the fight without severe casualties) In the longer haul this perversely becomes a bit of a strike against it, as there are ways to arrange completely passive capped resistances in Dark Side, at which point Magic Armor won't do anything, but still, it gets more opportunity to shine than in Warriors of the North if only because Dark Side is broadly more skewed toward defensive play.
Note that Warlock affects it; Level 3 Magic Amor backed by Rank 3 Warlock gives you 39% global resistances, not 30%. Defiler also boosts its duration, allowing it to reach a duration of 5 turns.
Though conversely it no longer scales with Intellect; neither its resistances nor its duration go up with Intellect. So that's a bit of a loss compared to Warriors of the North.
This is probably its high point in the series, overall.

Battle Cry
Crystal Cost: 3 / 12 / 20
Mana Cost: 5 / 10 / 15
Level 1 Statistics: Initiative: +1; Adrenaline/Frenzy: +5%, Duration: 2 turns
Level 2 Statistics: Initiative: +2; Adrenaline/Frenzy: +10%, Duration: 3 turns
Level 3 Statistics: Initiative: +3; Adrenaline/Frenzy: +15%, Duration: 4 turns
Increases Initiative of all allied units. Orcs and Demons generate additional Adrenaline/Frenzy by a percentage from combat.
Now it affects the new Frenzy mechanic on Demons, though instead of providing up-front Adrenaline/Frenzy it somewhat boosts the amount generated at a time. For units that are going to get into the thick of things, this is probably actually more useful, but for fueling units not getting into the thick of things it's a bit of a downgrade. In any event, this is probably the most useful it is in the entire series, and for Orc and Demon armies opening a battle with it is a really good idea if you're not playing Daert.
Somewhat lessening its importance is the overhaul to Onslaught and the addition of Foresight. Specifically, since Onslaught scales down over turns instead of vanishing instantly even at Rank 3, where in prior games it was often really important to cast Battle Cry on the first turn so you'd retain Initiative advantage on the next turn as well, late in Dark Side you'll often hold onto Initiative advantage all the way to the third turn. And if you kill all the enemies who have high enough Initiative for you to care by that time? Well, never mind Battle Cry then.
As an aside, just as with Sacrifice, there's a late-game Quest that calls for giving up a Battle Cry Scroll. If you're an obsessive completionist, you should hold onto a Battle Cry Scroll for that Quest so you don't have to go hunting for which store they're in later.
Note that Warlock boosts the Initiative increase, resulting in a maximum of +4 Initiative.

Peacefulness
Crystal Cost: 3 / 3 / 3
Mana Cost: 5 / 7 / 10
Level 1 Statistics: Damage: -30%; Health: +20%; Adrenaline/Frenzy: -5%, Duration: 3 turns
Level 2 Statistics: Damage: -30%; Health: +35%; Adrenaline/Frenzy: -10%, Duration: 4 turns
Level 3 Statistics: Damage: -30%; Health: +50%; Adrenaline/Frenzy: -15%, Duration: 5 turns
A single unit -ally or enemy- has its HP increased while its Damage is decreased. Orcs and Demons additionally generate less Adrenaline/Frenzy by a percentage.
Peacefulness provides less Health below the final level, and the Adrenaline subtraction has been shifted to a reduction in generation rate, while also being extended to Frenzy. This makes it something to use as a pre-emptive measure to make a Demon or Orc less threatening, rather than a way to immediately shut off access to a Talent on Orcs. In the case of Demons the distinction isn't super-important, since Frenzy isn't directly manually spent anyway, and since Adrenaline Levels aren't a thing anymore anyway the change is less striking than you might think when it comes to Orcs, too.
I'm not sure why the Health scaling was adjusted, though. Maybe to make Priestesses of Blood a little less abusable?
Admittedly Warlock boosts the Health bonus, resulting in the maximum possible boost actually being +65% Health.
In any event, I've... personally never bothered. Priestesses of Blood can generate infinite troops from infinite summons, making efficiency per se a luxury rather than any kind of necessity, and the Adrenaline/Frenzy-slowing mechanic is largely irrelevant in its offensive uses. You almost never fight Orcs, and you fight Demons only slightly more often than that, giving you little opportunity to try to leverage it.
Alas.

Dragon Arrows
Crystal Cost: 2 / 3 / 4
Mana Cost: 3 / 4 / 5
Level 1 Statistics: Gives Dragon Arrows: 1
Level 2 Statistics: Gives Dragon Arrows: 2
Level 3 Statistics: Gives Dragon Arrows: 3
Grants a single allied archer-class unit (Bowmen/Bowmasters, Elves/Dark Elves, Hunters/Rangers, Skeleton Archers) charge(s) of the Dragon Arrows Talent. This Talent is a ranged attack that entirely ignores the target's Resistance and ignores 30% of the target's Defense, and regardless of the user's own range will never suffer damage penalties from being fired too far. The base damage is derived from the unit's base damage. The damage type is Astral
.
Dragon Arrows no longer scales its count to Intellect, which is a pretty heavy nerf to it, though it probably hurts more that Dark Side overall shifts the pressure of what's good to use to units that aren't actual bow users. It also starts cheaper and ends more expensive, instead of having a flat cost, though you're still getting more Dragon Arrows for your Mana by leveling it.
On the plus side for Dragon Arrows, Skeleton Archers are by far their best abuser, and you're guaranteed early supplies of them. On the minus side, your options are functionally sharply limited since Elves/Dark Elves and Hunters/Rangers take so long to gain access to and Bow Masters don't get long-term lifetime supplies if we don't count abusing Sacrificing.
As noted previously, Amazons have code for being able to benefit from Dragon Arrows, but are not properly tagged to be targetable with it, so Dark Side has no new Dragon Arrows abusers.
Also note that the Defiler Skill can add up to one additional charge to Dragon Arrows. This is consistent with Dragon Arrows historically using the duration-extension logic for adding additional duration, but still unusual.

Fit of Energy
Crystal Cost: 6 / 6 / 6
Mana Cost: 14 / 17 / 20
Level 1 Statistics: Gives Action Points: 1, Level: 1-2
Level 2 Statistics: Gives Action Points: 2, Level: 1-3
Level 3 Statistics: Gives Action Points: 3, Level: 1-4
Grants a single allied unit additional Action Points. If its turn was over, it gets an additional turn to use these Action Points.
Fit of Energy's cost has been reduced below the final level, though not by a lot: you're still getting more AP per Mana when upgrading it. It also now has a Level limitation, which is a bit more surprising to me. Was there a trend of higher-level units being better at abusing Fit of Energy in prior games that I overlooked?
Personally, I only rarely used Fit of Energy in prior entries, and I'm not sure I've ever cast it in Dark Side.
Do note that Warlock can add an additional action point. Gifting 4 action points is that bit more flexible/mobile than 3.

Helplessness
Crystal Cost: 1 / 2 / 4
Mana Cost: 2 / 4 / 6
Level 1 Statistics: Defense: -30%; Duration: 3 turns
Level 2 Statistics: Defense: -45%; Duration: 4 turns
Level 3 Statistics: Defense: -60%; Duration: 5 turns
Lowers a single enemy's Defense by a percentage.
Never touched by any game in a direct sense.
That said, Warlock can raise the Defense penalty to up to -78% (Even harsher than the Warriors of the North max!), and Defiler can extend its duration to a maximum of 6 turns.

Summon Phoenix
Crystal Cost: 10 / 15 / 20
Mana Cost: 20 / 25 / 35
Level 1 Statistics: Summons: Young Phoenix
Level 2 Statistics: Summons: Mature Phoenix
Level 3 Statistics: Summons: Ancient Phoenix
Summons an allied Phoenix in a chosen tile. The tile must be adjacent to an allied unit. You may only have one Phoenix on the field at a time.
The Spell itself is completely unmodified from Warriors of the North.
But where previously the Phoenix got a halved boost from summon-boosting Skills, Puppeteer in Dark Side provides its full boost!
Anyway, stat time!

Young Phoenix
Level: 3
Leadership: 1
Attack/Defense: 15 / 10
Initiative/Speed: 5 / 5
Health: 200
Damage: 40-60 Fire
Resistances: 80% Magic
, 80% Fire
, -100% Ice
Talents: None
Abilities: Flight, Firestorm (Melee attacks and counterattacks not only hit the target but enemies to the side, and have a 70% chance Burning everyone. No friendly fire), Immune to Fire (80% Fire resistance, cannot be Burned), Magic Immunity (80% Magic resistance, spells don't effect the unit), Rebirth (The Phoenix can, once, revive after a delay. Resurrecting is not possible if a unit is occupying their corpse's space, and the act of resurrecting consumes their entire turn)
The unit is also unchanged from Warriors of the North. This includes being inorganic.

Mature Phoenix
Level: 4
Leadership: 1
Attack/Defense: 40 / 30
Initiative/Speed: 6 / 6
Health: 400
Damage: 70-100 Fire
Resistances: 80% Magic
, 80% Fire
, -100% Ice
Talents: None
Abilities: Flight, Firestorm (Melee attacks and counterattacks not only hit the target but enemies to the side, and have a 85% chance of Burning everyone. No friendly fire), Immune to Fire (80% Fire resistance, cannot be Burned), Magic Immunity (80% Magic resistance, spells don't effect the unit), Rebirth (The Phoenix can, once, revive after a delay. Resurrecting is not possible if a unit is occupying their corpse's space, and the act of resurrecting consumes their entire turn)
Also untouched.

Ancient Phoenix
Level: 5
Leadership: 1
Attack/Defense: 60 / 50
Initiative/Speed: 7 / 7
Health: 800
Damage: 140-240 Fire
Resistances: 80% Magic
, 80% Fire
, -100% Ice
Talents: None.
Abilities: Flight, Firestorm (Melee attacks and counterattacks not only hit the target but enemies to the side, and have a 100% chance of Burning everyone. No friendly fire), Immune to Fire (80% Fire resistance, cannot be Burned), Magic Immunity (80% Magic resistance, spells don't effect the unit), Rebirth (The Phoenix can, once, revive after a delay. Resurrecting is not possible if a unit is occupying their corpse's space, and the act of resurrecting consumes their entire turn)
Also unchanged.
Personally, I've never used Summon Phoenix in Dark Side, but that's in part commentary on the fact that I've never lucked into the Scroll early enough. If you were to find it early -which is entirely possible, as there's an Ore Cart in Dragandor during what I think of as the 'prologue' portion of the game that can have any Scroll in the game- it could certainly be quite useful for any character/class.

Call of Nature
Crystal Cost: 4 / 8 / 12
Mana Cost: 20 / 30 / 40
Level 1 Statistics: Level up to 2; Troop Leadership: 30%
Level 2 Statistics: Level up to 3; Troop Leadership: 50%
Level 3 Statistics: Level up to 4; Troop Leadership: 70%
Summons a random animal stack into a tile adjacent to an existing player unit. The stack can act on that turn.
Call of Nature has been subtly overhauled. Now the Leadership is a percentage of your own, as I noted about summons back in Chaos Magic, and also Werewolves have been cut from the list of summons. Here's the exact list from the .txt file:
bear, bear2, bear_white, graywolf, snake, snake_green, snake_royal, griffin, griffin2, dragonfly_fire, dragonfly_lake, hyena
Which is just 'the list from Warriors of the North and Armored Princess, minus Werewolves'.
Of course, in Dark Side summons of this sort outright increase the stats on the units by a percentage in cases where you would summon more than your Leadership can support (And Call of Nature isn't bugged to not use this logic), so Call of Nature has been further modified by that. Call of Nature has always been a solid Spell, but in Dark Side it's astonishingly powerful, with Daert in particular able to, in the late game, basically crush entire armies with a single Call of Nature if you care to. It's pretty ridiculous, and I suspect is a casualty of insufficient playtesting.
It's also your go-to Spell option for generating fodder to Sacrifice up more troops via Priestesses of Blood, so once you've got it you can largely ignore quantity limitations on units if you're willing to spend time on such shenanigans.

Avenger
Crystal Cost: 7 / 10 / 15
Mana Cost: 15 / 20 / 25
Level 1 Statistics: Damage: 160-240, Duration: 4
Level 2 Statistics: Damage: 290-430, Duration: 5
Level 3 Statistics: Damage: 415-625, Duration: 6
A single target ally is granted a buff which decrements by one turn each time the unit takes damage from any enemy unit via any means. (Except for over time effects like Burning) The injuring unit is retaliated against by Magic
damage.
Avenging Angel has been given a new name and Spellbook graphic, because you're playing Team Mordor and so angelic support is obviously inappropriate, but its actual mechanics are unchanged.
It's also, possibly accidentally, had its base damage substantially improved -doubled prior to Level 3, and a bit more than doubled at Level 3!
Also note that Items that boost Lightning damage still apply to it, that Warlock can give it a maximum duration of 8, and oddly where previously Creation (ie the 'boost helpful Spells' Skill) boosted its damage now Wight boosts its damage. (ie the general damage booster Skill)
In real terms this is probably its worst game, because Dark Side is so dramatic in class differentiation. Daert will have hilariously strong Avenger damage, but his armies are tiny and weak and he's better off nuking everything to death with direct attacking Spells like Fire Rain. Bagyr and Neoline are much more open to having their units get into the thick of things with enemies, but their Avengers will be pathetically weak.
Oh well.
I personally skip learning it. 7 Magic Crystals is pretty painful, and it's still not great.

Power of Night
Crystal Cost: 3 / 3 / 25
Mana Cost: 5 / 10 / 25
Level 1 Statistics: Bonus Damage: 10%; Duration: 3 turns
Level 2 Statistics: Bonus Damage: 20%; Duration: 4 turns
Level 3 Statistics: Bonus Damage: 20%, Mass; Duration: 4 turns
The unit's base attack and damaging Talents does additional damage against Of The Light units. It cannot be cast on Elves, Dwarves, Humans, or Vikings. At Level 1 it also cannot be cast on Neutral units.
The primary actual change is that Snow Elves don't exist, which is kind of a non-change since it's bugged in Warriors of the North to not boost damage against Snow Elves. The secondary change is that Vikings are no longer in the list of things it boosts damage against, for whatever reason.
In theory, this is a nice general buff in damage. In practice the damage is too low; if the target doesn't have resists, Chaos Weapon is better, and I already laid out how Chaos Weapon isn't even that good. Alas. It does benefit from Warlock so its true maximum boost is +26%, but... doesn't change the point.
Note that the anti-Light damage is based on internal tagging separate from the explicitly-listed Of The Light Ability. This is thus one of the cases where the internal tagging being wrong on a few units can theoretically matter -a Darkwood Ent will take bonus damage from a unit boosted by Power of Night, for example, even though it's supposed to be a Dark unit.

Power of Light
Crystal Cost: 3 / 3 / 25
Mana Cost: 5 / 10 / 25
Level 1 Statistics: Bonus Damage: 10%; Duration: 3 turns
Level 2 Statistics: Bonus Damage: 20%; Duration: 4 turns
Level 3 Statistics: Bonus Damage: 20%, Mass; Duration: 4 turns
The unit's base attack does additional damage against Of The Dark units. It cannot be cast on Traitor Humans, Zwerg, Dark Elves, Orcs, Demons, or Undead. At Level 1 it cannot be cast on Neutral units.
The primary change is that Lizardmen and Undead Lizardmen are gone and have been replaced by the Dark versions of Light races.
Though it has the same underlying points as Power of Night: Warlock can raises its boost to +26% at maximum, its damage bonus is applied based on internal tagging (And so it won't actually give bonus damage against eg Orc Shaman because they're not properly tagged as Of The Dark internally), and the new minor point of not being castable on Neutrals at Level 1.
Curiously, the .txt file refers to 'Dark Vikings', even though Vikings are not made part of the Light/Dark division of the game. It makes me wonder if they'd intended to have the player convert Vikings to the dark like they do Humans, Dwarves, and Elves, and ended up dropping the concept, and missed the reference in this particular Spell's coding. And if so, I'm curious as to why it was dropped: it honestly wouldn't surprise me to learn that they struggled to properly Dark-ify the Viking art style, as they have such an unusual art style compared to the rest of the game. Or it could just be the general rushed-ness of the game in action.
Regardless, the Spell itself is borderline-worthless in the player's hands in Dark Side, as you'll almost always be using an army that can't even make use of the Spell and you'll only occasionally face foes the Spell benefits you for fighting.

Last Hero
Crystal Cost: 1 / 3 / 5
Mana Cost: 5 / 7 / 10
Level 1 Statistics: Target's Level: 1-2; Duration: 3 turns
Level 2 Statistics: Target's Level: 1-3; Duration: 4 turns
Level 3 Statistics: Target's Level: 1-4; Duration: 5 turns
A single targeted ally takes no damage from effects for the duration, with each hit suffered reducing the duration of Last Hero by 1 turn. Once Last Hero runs out, all the damage that was blocked by Last Hero comes back. Additionally, the unit has unlimited retaliations.
Last Hero has been mugged from Rune Magic, and critically it's finally been made genuinely worth considering: delaying damage with no trade-off aside the casting per se is genuinely worth considering, especially if eg you're fielding Warrior Maidens, where timing of casualties actually matters!
Do note that the bug where a Furious unit becomes Passive if you cast Last Hero on them remains present.

Winter's Dance
Crystal Cost: 5 / 7 / 10
Mana Cost: 10 / 15 / 20
Level 1 Statistics: Damage: 45-65
Level 2 Statistics: Damage: 95-135
Level 3 Statistics: Damage: 145-210
Does Physical
damage to all units in a circle, with the center being safe.
Another Spell mugged from Rune Magic. Its actual numbers and whatnot are unchanged, but it no longer ignores Spell immunity. Its presence is most notable for being another strike against Axe of Magic: why do decent Physical damage to a single target for far too much Mana when you could hit multiple targets for only slightly more Mana, ending with overall more damage and also getting more chances for things like Bleed-from-crit? If you're hitting even two targets, Winter's Dance will probably roll high enough to beat Axe of Magic, and if you hit three Winter's Dance is winning, period.
... well, its numbers are supposed to be unchanged, but due to bugs it actually uses Avenger's Level growth rates, which are worse than its own numbers; as such, it levels more poorly than in Warriors of the North.
It tends to fall away in relevance as your options expand -if you've got Fire Rain in particular Winter's Dance is nearly entirely displaced- and because of it leveling poorly, but it can be surprisingly useful for a surprisingly large chunk of the early-to-midgame, depending on your luck with Scrolls.

Shelter
Crystal Cost: 3 / 3 / 3
Mana Cost: 4 / 7 / 10
Level 1 Statistics: Duration: 3 turns
Level 2 Statistics: Duration: 6 turns
Level 3 Statistics: Duration: 9 turns
A single target ally is rendered innocuous: for the duration of the Spell, enemy units won't deliberately target the unit. If the unit performs an attack, the Spell will break, and each time a unit could have attacked the Sheltered unit but did not, the Spell's duration is reduced by 1.
I don't really get Shelter. It's basically a kind of nerfed Invisibility that happens to be a lot more interesting than Invisibility, which doesn't really matter because Invisibility is still in the game.
You're not going to actually use it, is what I'm saying.
This isn't even getting into the buggy point that its duration reduction is prone to deciding a unit could've attacked the Sheltered unit even though it couldn't have.
It does at least work on Eyeless creatures, unlike Invisibility, so that's... something?

Creation
Crystal Cost: 3 / 5 / 7
Mana Cost: 8 / 12 / 16
Level 1 Statistics: Target's Level: 1-2; Charges: 1, Adrenaline: 15
Level 2 Statistics: Target's Level: 1-3; Charges: 2, Adrenaline: 30
Level 3 Statistics: Target's Level: 1-4; Charges: 3, Adrenaline: 45
A single target ally gains charges to all its charge-based Talents. If used on an Orc, the Orc instead immediately gains Adrenaline.
It's Gift from The Legend, but cheaper and stuff. It's kind of ridiculous.
I'd complain about the exploitive stuff it opens up, but Dark Side has much more accessible and general exploits like Blood Priestesses. I've actually cast Creation only a bare handful of times across my runs, and not because I was restraining myself from abusing brokenness. It's just not that relevant when I can do crazier stuff.
Do note that Warlock boosts both the charges it adds and the Adrenaline it gives to Orcs, resulting in a maximum of +4 charges and +58 Adrenaline. Also note that if used on a unit that you've cast Dragon Arrows on before, it will give additional Dragon Arrows charges.

Empathy
Crystal Cost: 3 / 6 / 9
Mana Cost: 3 / 6 / 9
Level 1 Statistics: Duration: 3, Damage Transferred: 10%
Level 2 Statistics: Duration: 6, Damage Transferred: 20%
Level 3 Statistics: Duration: 9, Damage Transferred: 30%
Picks a target allied unit and a target other unit, friend or foe: a percentage of the damage dealt to the first unit is transferred to the second unit instead. (The transferred damage is untyped, and so ignores resistances) Cannot be Dispelled.
As with Thread of Life etc, Empathy's in-game description claims that you select two allies, and in actuality you can and should use it to shunt damage to an enemy instead.
Like many new Dark Side Spells, Empathy is a very wonky Spell with lots of odd behavior you're unlikely to intuitively expect and which can be very frustrating to run into when playing the game blind: firstly, the Spell's logic breaks entirely if you get the transfer rate to 100% or more, resulting in it ceasing to transfer damage. As it actually scales with Intellect, it is entirely possible for this to happen; when you're playing Daert particularly it's basically guaranteed that you'll eventually end up with the Level 3 version simply ceasing to function. (And it's possible for a Daert run to even get the Level 2 version non-functional in the extreme late game, though not in an unavoidable manner) A Daert run may wish to skip the Level 3 version as Magic Crystal counts are an actual limitation in Dark Side. This is particularly unfortunate given that ideal usage is to have the transfer rate very, very close to 100%, and thus be at the point that just a little more Intellect can suddenly break your Spell. You can just cast lower-Level versions, of course, but dropping from 99% transfer rate to 68% because your Intellect rising pushed your 99% to 102% is a pretty big drop in effectiveness.
The breakpoints for this are that if you have Warlock 1, 56 Intellect breaks Level 3 Empathy, if you have Warlock 2 then 46 Intellect breaks Level 3 Empathy, and if you have Warlock 3 than roughly 42 Intellect breaks Level 3 Empathy. For Level 2 Empathy, if you have Warlock 3 then 103 Intellect will break it -this is feasible for Daert to reach, but for Bagyr and Neoline I have doubts they can get that high of Intellect. (Dark Side is enough of a buggy mess I won't be surprised if someone discovers a way to get massive Intellect through bug exploitation, but outside such a scenario Bagyr and Neoline shouldn't be able to get so high) So those are the numbers to keep in mind if you're wanting to lean into Empathy usage.
Second, it should be noted that Empathy specifically splits damage after all other modifiers have gone through. Say you have Empathy at 50% transference and cast it on a Red Dragon stack, while having enough resistance boosters the Red Dragon stack has 95% Fire resistance; if you then have your Red Dragon stack pick a fight with a Black Dragon stack, what will happen is both the Red Dragon and the Empathy victim will take an equally-sized tiny amount of damage. (Even if the victim is a Plant or something) As such, if you're specifically wanting Empathy to act as a kind of damage source (Such as by using it on a summon you hurl to its death), you'll actually want to not boost the recipient's resistances or other defenses. (ie don't slap Stone Skin or Magic Armor on your suicide unit)
Third, Empathy for some reason causes the beneficiary taking damage to produce bizarrely huge amounts of Rage, generally instantly maxing your Rage. I'm not sure why; I'd expect it to reduce Rage gained, given it reduces the damage the unit takes. Whatever underlies this oddity, the result is that Bagyr appreciates it as a way to fund his absurd Rage spam, and Daert appreciates it as a way to offset his normally poor Rage generation.
Fourth, Empathy cannot be cast on a unit currently benefiting from it, and Empathy doesn't terminate just because the transfer target dies. In conjunction with its high duration and the inability to Dispel it, having a 'designated tank' can go wrong if you're not expecting this odd combination of behavior, where you're expecting to re-Empathy your designated tank to change who is the victim and whoops the game won't let you. (Empathy only blocks damage if there's a target to transfer the blocked damage to)
With a very high transfer rate, Empathy becomes near-invulnerability to the beneficiary: transferring 99% of incoming damage can mean a unit can be hit for thousands of damage and only take a few dozen points of damage, which for a decently tough unit won't necessarily result in even a single casualty. This is one way Healing providing healing can actually be relevant, and of course you're turning the enemy's own damage against them: among other points, this means once you have Empathy at a very high transfer rate you can take on very outsized battlegroups, because Empathy 'auto-scales' to group size. Against battlegroups whose targeting is easy to control (Ones heavy on slow melee attackers, for example), Empathy with a high transfer rate can let you beat an 'out of depth' fight with no casualties almost on its own.
Helping it is that the game's logic is oddly favorable to the player. I'm unsure what the game's exact rules here are, but the game is unexpectedly willing to transfer over 99% damage when its stated rate is 99%. The difference between transferring 99% vs transferring 99.5% might not sound like much, but the latter scenario is twice as good at keeping the beneficiary alive.

Warded Healing
Crystal Cost: 8 / 12 / 18
Mana Cost: 5 / 10 / 20
Level 1 Statistics: Block Total: 50, Individual Block: 10, Duration: 3
Level 2 Statistics: Block Total: 125, Individual Block: 25, Duration: 4
Level 3 Statistics: Block Total: 200, Individual Block: 40, Duration: 5
A single target non-Dark ally will, for a number of turns, block up to a small amount of damage per hit against them. There is additionally a per-cast cap on its ability to block damage, which consistently works out to 5 times the per-block amount. Inorganic units are ineligible. At Level 3, casting Warded Healing on a unit already benefiting from Warded Healing will simply add the maximum block potential to the existing supply of block, where at lower Levels it will reset it to the listed amount, wasting any remaining block amount.
The in-game description of Warded Healing really sounds like the target takes damage and then is healed, but in actuality it outright prevents some damage before anything happens. This makes Warded Healing always useful, no matter what unit you're considering casting it on, unlike the basic Healing Spell, as it can prevent casualties, or even fully block damage if the attack was weak enough relative to Warded Healing.
As with Healing, Warded Healing is a Spell you shouldn't learn manually -especially since its basic Crystal cost is quite high- and should instead take advantage of the Quest to turn three copies in and get it upgraded to working on everything. Unlike Healing, it can be surprisingly useful for a surprisingly long time; Daert in particular may actually consider using it in the mid-late game if it would be useful to get a unit into a dangerous position but you'd prefer to minimize its casualties, as he can get it blocking several hundred damage per activation.
Note that Defiler boosts the block potential, both the total cap and the per-activation amount. Also, an oddity that is unlikely to come up in normal play is that if a given block manages to be greater than the full damage of a given hit, the game will actually remember fractional damage absorbed by Warded Healing, where usually the game endeavors to avoid fractions in final/visible-to-the-player numbers.

Ball of Lightning
Crystal Cost: 5 / 10 / 15
Mana Cost: 8 / 14 / 20
Level 1 Statistics: Damage: 100-200 Duration: 2
Level 2 Statistics: Damage: 200-400 Duration: 3
Level 3 Statistics: Damage: 300-600, Duration: 4, Target Redirection
Generates a high-flying ball of lightning that once per Round attacks a single enemy for Magic
damage with a 10% chance to Shock the target.
It's (almost) literally Ball of Lightning/Mista's Lightning, the Rage moves, except now it's non-percentile damage. Like the Armored Princess Ball of Lightning, it attacks on the first Round it's out. Unlike the Rage moves of prior games, it pursues a particular target relentlessly and vanishes if that target is wiped out... until you've got it at Level 3, at which its initial target being destroyed causes it to switch to picking a random target per Round until it times out.
Oddly, though you can set its initial target to be an Object, the Level 3 random-target behavior will never select an Object as a target. Also, Defiler affects its maximum duration, but the game can get confused; the maximum duration backed by Defiler should be 5 turns, but a Ball of Lightning can end up buggily lasting a lot longer than that. As for Ball of Lightning's Initiative, it's 10, much like the prior Rage-based lightning balls. Also note that Items that boost lightning damage do absolutely include Ball of Lightning.
Ball of Lightning is probably one of Order's best relatively direct damage Spells in Dark Side as it's reasonably affordable and the fact that it strikes multiple times per cast means its listed damage per hit is misleading, especially as you level it and your Intellect climbs, extending its duration and thus number of hits, all with no risk of friendly fire or the like. I'm quite fond of it on a design level: it's the first damaging Order Spell that's really good and worth using without pushing into Chaos' dominance over damage-on-demand.
Also boosting its effectiveness is that, like Avenger, the game actually doubles its base damage; ostensibly its base damage should be half the above numbers. This would've made it weaker per-hit than Lightning initially, instead of its current state of being very much purely better than Lightning out the box.
How practicable it is in real play depends a bit on luck. If you get a hold of Ball of Lightning early in the game in a Daert run, it can be a staple damage Spell for a fairly large chunk of the game, including being one of your better options for your first cast in a turn so long as your Higher Magic rank is equal or greater than your Order Magic rank, particularly once it's Level 3 where it'll just jump targets if the original target dies. On the other hand, if you eg find Rain of Fire hours before you ever spot Ball of Lightning, or you only get Ball of Lightning late in the game when Daert can expect to routinely finish a battle in 1-2 turns on Spellslinging alone, Ball of Lightning is more or less completely worthless to you. It's also of dubious use for non-Daert characters in general.
Still, I very much appreciate Dark Side coming up with an attacking Order Magic Spell that isn't a clone of some other Spell and doesn't completely undermine Order being the weakest school for offensive magic. It's really well-designed, and it's just an unfortunate casualty of Dark Side having serious problems in other realms. It's one of the better examples of what Dark Side could have been if the developers had been allowed to polish it.
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Next time, we wrap up Spells with Distortion Magic.
'cause Rune Magic is gone. I already mentioned that. It's not missed, really.
See you then.