)Lore of Slaanesh
Lore Attribute: Bliss in Torment (Warriors of Chaos)
Nothing to write home about. For every wound caused by the Slaanesh magic, roll a d6 and on a 6 you get +1WS, I and A. So on average you need to cause 6 wounds with Slaanesh magic (which isn't known for mass damage) to get +1 to these stats. It can come in handy now and then and can certainly swing combat, but its lack of reliability is something you shouldn't worry yourself with. Important: Any damage caused by any spell in this lore negates the Ward save of our Warlocks!
Lore Attribute: Born of Damnation (Demons of Chaos)
This Attribute is in my opinion considerably better than its Warriors counterpart. You pick either a unit of Demonettes or Fiends of Slaanesh within 12" and for each wound caused by slaanesh spell roll a d6, on a 5+ a demonette is added to the unit of demonettes, on a 6 a fiend is added to a unit of fiends. What makes it considerably better is that you get to choose which unit you want to try to add models to after casting the spell so it's tricky to know if you want to stop the spell just to stop the attribute. Unless there's only one target, you simply won't know. Why is it considerably better? Because you can pick the target based on the number of wounds caused. With low number of wounds, it's more beneficial to try for some demonettes, but if you cause a lot of wounds (like with a successful area Choir), you can attempt to bring multiple additional Fiends to a nearby unit. Be wary of this attribute, while demonettes die fast, extra fiends can cause a lot of trouble.
S: Lash of Slaanesh
It has a nice range at 24" but the fact that it only hits as many models as a straight line goes over severely limits the spell's usage. If it's cast from the front of the unit, I wouldn't bother dispelling it. Taking a couple S3 hits with AP is something even we can survive. It becomes more problematic if the sorcerer is mounted or flying allowing him to line up a sideways spell, potentially hitting multiple units and even going across a unit of warlocks which can cause some hurt. Pay attention where the sorcerer is going and dispel accordingly. Like with any spell, the caster has to determine where he's going to cast it before rolling dice so you will know if you should bother dispelling it.
1: Acquiescence
This spell does no damage, instead it does what Slaanesh magic is notoriously known for. It controls the movement of their enemies. Considering how important movement is for us it's one of the priority spells to dispel. Adding ASL on top of the random movement is just rubbing salt onto the wound. There is a but though since the spell does no damage. Having your unit random movement (even d6") means you can suddenly make really short charges in any direction as per random movement rules. If your opponent is not careful he might cause himself more harm than good if it happens to enable your units to charge at an odd angle thanks to the Random Move. In those situations (few and far between) it can be worth it to suffer ASL for a turn (or even better if it's cast on Execs who already have ASL) to turn the spell into your advantage.
2: Pavane of Slaanesh
Character sniper unlike the other ones available to other armies, this one forces a Ld test on 3d6 and the character takes a wound with no armor saves. Here's the downside of the spell - it only causes a single wound so you will know fully well when your character is at risk of dying from it. Remember it's a Leadership test so you do benefit from BSB re-roll as well making the spell rather underwhelming. I wouldn't worry about it too much unless it's being cast on one of our monsters outside of General's range as they have crap for leadership. It also automatically wounds the Cauldron (as it has Ld-) but will have to go through the 3++ that the Cauldron has against spells so again, nothing to worry about too much. I can see this spell being used to ping off the last wound more often than not.
3: Hysterical Frenzy
This one can be cast either on friendly or enemy units, giving them the Frenzy special rule. Usually, it will be cast on a unit that is already in combat to boost their performance, in which case you know you want to dispel it. Chaos Warriors are deadly enough without having extra attacks. If cast on one of our units, it also makes them frenzied (with the added benefit of giving +2A if the unit is already frenzied by itself). As an additional effect, the unit this spell's been cast on takes d6 S3 hits at the end of magic phase (so it will always take at least that d6 hits). It does allow for armor saves so most chaos units will be largely immune to the damage, especially knights, while it's unlikely that it will be cast on our knights. Even so, with a large enough infantry unit you can take a few hits from it. The problem shows up when our unit with this spell on reaches combat. Since it's remains in play, it can be dispelled by the caster at any point so don't expect to benefit from the extra attack except against forgetful opponents. I wouldn't worry too much about the damage unless it's cast on a small unit since the spell is RiP and not very hard to dispel in your following magic phase. Worry about it if its being cast on warriors already in combat, and don't let it be cast on warlocks!
4: Slicing Shards
A very random spell that can be extremely powerful... or a dud. D6 S4 hits doesn't sound like much (even though S4 hurts us elves pretty badly), but it then forces you to take a Ld test and if you fail you take another D6 hits and another test. It continues until you either pass the Ld test, or the target is all gone. It can be pretty deadly if cast on a stranded monster, it may be S4 but with their low Ld they are bound to take plenty of hits. If you feel you can take the damage from one d6, have your general and BSB nearby then don't worry about dispelling it. There are worse spells in the lore and we have universally high Ld (unless it's cast on a lone Cauldron... then it will always destroy it as it's impossible for the cauldron to pass an Ld test. A rare situation but it could happen).
5: Phantasmagoria
The spell adds an extra d6 to all Ld tests done by the target (or all units within 24" of the caster if boosted) and discard the lowest die. A reverse of Cold Blooded of sorts. By itself not too terrible as Chaos doesn't have too many means of causing Panic (beware if there's a Hellcannon on the field) but it can be combined to some nasty effects extra D6 for Pavane of Slaanesh or Slicing Shards will greatly increase their success rate so try not to let both of the spells through. You also don't want to see it cast on your units in combat as fighting Chaos in melee is difficult already without them having magical help. Watch the battlefield and decide if it can have a big impact before committing your dice.
6: Cacophonic Choir
This is the spell that makes Lore of Slaanesh. Thankfully Chaos has no means of picking spells so there's a chance that the Slaanesh wizard won't get this spell. If they don't, sigh with relief and know your magical dominance is half done already. If they do... well, do your best not to let them cast it. Because it's a hex, it can affect units in combat (and it's a common tactic it seems for the Demon Prince to engage in combat somewhere with plenty of targets around and cast it). Each affected unit (12" bubble around caster when boosted) takes 2d6 hits that wound on 4+ regardless of Toughness and don't allow for armor saves. This spell literally destroys armies if cast at the right moment. Sure the boosted version is pretty hard to cast, but often a single high value target is enough to make the spell worthwhile. If that wasn't enough, if the target takes any wounds, they are affected by ASL and Random Move d6 like from Acquiescence. Beware of this spell, don't let it be cast.
Lore of Tzeentch
Lore Attribute: Boon of Magic (Warriors of Chaos)
This attribute is nothing to plan for, when any spell is cast, every die that turned up 6 is put back in the casting pool but only the caster can use it. Ok, sounds great on paper, until you realize that two 6s is a miscast and multiple miscasts take away d6 power dice from the pool. This attribute will add an extra die from time to time but it's nothing compared to Death Magic attribute.
Lore Attribute: Fires of Change (Demons of Chaos)
This is pretty much a carbon copy of the Slaanesh demons attribute (and as a shocker, the Nurgle one does the same thing), except instead of Demonettes we have horrors and instead of fiends we have Screamers. There is a notable difference though, Units of horrors get better the bigger they are, and with their ability to cast tzeentch magic, it means they can self regenerate for every spell they cast. Pretty nifty.
Signature: Blue Fire of Tzeentch
Easy to cast, simple magic missile of a pretty standard range. The randomness of its strength can be worrying but it's as likely to be S6 as it is to be S1. The fact that it only causes d6 wounds makes it only a threat, and an unreliable one at that, to small units of dark riders or shades. If the targeted unit is important, go ahead and dispel it. Otherwise there are far more dangerous spells in Tzeentch's repertoire to be worried about.
1: Treason of Tzeentch
The spells is relatively easy to cast and can be devastating depending on target. The target of the spell has to use the lowest Ld value instead of the highest. Now there's some debate here on whether if makes you use Mount's Ld (BRB states Mounts' Ld is never used, but the AB states use lowest. AB vs. BRB contradiction? That is my theory and that's how I treat the spell). Assuming it forces the unit to use its real lowest Ld: Cold One Knights will be stupid all the time, Witch Elves with Cauldron will never pass frenzy check (remember Cauldron's crew is Ld-) etc. This also affects combat so if your knights or cauldron were to lose combat, it's bye bye time. If your local area rules that mounts are excluded from "lowest Ld" then don't worry about this spell. We have at least Ld8 which is solid enough to let your opponent waste some power dice. Just like Shroud of Despair the spell prevents the use of Inspiring Presence and Hold your Ground! rules so even if you won't be using Ld of the mounts, try not to let it be cast into combats you might end up losing as that BSB re-roll is often crucial.
2: Pink Fire of Tzeentch
Flame template spell with an effective range of 8-18" (artillery die plus flame template length). This makes it pretty unpredictable as it doesn't hit everything in the path like a vortex spell but only models under the template at the end of its travel. This may result in not getting enough range, landing too far and only hitting the target with the end of the template etc. On top of this, its strength is only d6 so even if you get a complete perfect hit... Murphy's Law says it will be S1. Cheap spell to cast but not one to worry about too much (unless it's aimed into the side of your horde of execs... then it's likely to hurt.
3: Bolt of Change
Tzeentch version of a bolt thrower. Easy to cast with a moderate range but again, really really random. The strength of the bolt is d6+4 so at the very least it's respectable. Doing d3 wounds it can cause some worry to our monsters and single characters (though a pegmaster with cloak should be able to take it). If shot at a unit I wouldn't worry about it unless it's a unit of knights as the Bolt ignores armor regardless of it's Strength, and even at S5 it will hurt our squishy T3 elves.
4: Glean Magic
Ok, if you have wizards, throw everything to dispel this spell. The risk of losing a spell and a level is not worth it. The spells is a wizard duel where both caster and target roll a d6 and add their level. If the caster wins, the target loses a random spell and a wizard level and the caster gains that spell! (Recently I saw a Tzeentch Wizard flying around with Soul Quench from High Magic) They will not gain the original attribute of the lore, retaining their Tzeentch attribute, but just the knowledge that your Word of Pain is now in hands of the enemy... No, nothing is worth that risk. Thankfully the spell is easy to cast so the Tzeentch wizard might use few dice and keep the rest for the big spell. If they do, dispel dispel dispel. Even if you win the caster duel and don't lose a spell, the wizard still takes an S3 hit.
5: Tzeentch's Firestorm
A scattering template of a D6S hits, it can be made into a bigger template and scatter 2d6" instead of d6" but still D6S. If your opponent has access to the infernal gateway this spell is likely never to be even attempted. But, if it is, just weigh your options. Glean Magic is more dangerous than this, Bolt of Change is more dangerous if you have targets for it, Infernal Gateway is more dangerous... This one is kind of hard to cast for its effect too. Definitely not a priority.
6: Infernal Gateway
The Infernal Gateway got toned down a LOT. It's still a dangerous spell but it will no longer remove entire units every 12 casts. It's relatively hard to cast for a 2d6 hits spell so it's unlikely to be cast on a large unit. Where its strength lies is the 2d6 S, which on average will yield S7 hits. Pretty powerful to reliably take down smaller units and expensive monsters. In case of 11 or 12 being rolled for S, it gets capped at 10, but additional d6 hits are inflicted. It can be pretty brutal... or it can cause 2 S2 hits... Tzeentch is fickle like that.
Warpflame
This is a special rule added to every tzeentch spell that causes damage (which potentially is all of them). When a model (or unit) takes an unsaved wound from a tzeentch spell, it has to take a S test at the end of magic phase. If failed the unit (or model) takes additional d3 wounds with no armor saves, but if passed the unit's regeneration goes up by 1 or if there was no regeneration in the first place, they get regeneration (6+) rule. While the regeneration will have little effect (it does last for the rest of the game and keeps stacking though so do keep track of it!) the extra d3 wounds can cause some havoc which makes judging the damage that Tzeentch spells can cause rather tricky. Since it's hard to predict these extra effects, focus on countering what's important and you'll be fine. Keep in mind - Tzeentch might have a lot of fire in the spells' names... but none of them are Flaming Attacks!
