The following sub-mechanic is shared for all chaos units on Interbellum.
There are 4 chaos corruption debuffs that each stack up to a maximum of 10 and last for 10 seconds. Chaos corruption is spread on the caster and enemies. Some rarer effects will spread them to allies. Some order characters have the ability to cleanse stacks of corruption from their allies.
Chaos corruption has both positive effects and negative effects which mathmatically cancel each other out in power level. Chaos racial tactic removes the negatives from all Chaos Corruption applied to you. Each specialization has a tactic that doubles the positive effects of corruption for the chaos god the spec is designed for.
Blood-marked is a Khorne skill debuff that lasts 8 seconds and can stack up to 3 times. Certain Khorne skills gain additional effects if the target is Blood-marked. Sleepy is a Slaanesh skill debuff that lasts 5 seconds. -25% accuracy and -25% movement speed for duration. Plagued is a Nurgle skill debuff that lasts 6 second and stacks up to 5. Deals ichor damage over time.
These values are per stack: Khorne – Gain 1% outgoing damage and 400 potency. Lose 1% damage reduction and 1.4% outgoing healing. Nurgle – Gain 31 HP4 and 1% damage reduction. Lose 200 accuracy and 250 ichor resistance. Slaanesh – Gain 1 adrenaline per second and 2% AP cost reduction. Lose 400 fortitude and 400 block. Tzeentch – Gain 2% reduced cast time and 1 second cooldown reduction. Lose 250 spiritual resistance and 115 sagacity.
Chosen -> Blightkings, Gorechosen, Tzeentch (unnamed)
Chosen are the best at applying corruption for their specific specialization than other chaos units. But their actual primary mechanics involves consuming corruption effects from the enemy in order to apply new powerful effects. Every spec of chosen has abilities that consume each of the 4 types of corruption.
This means Chosen are best whenever you have other chaos units hitting the same target as well as they support chaos units better. They can, however, perform their roles well even as the only chaos unit in the party.
Since this section is quite small just due the fact that chosen heavily use the corruption system; I’ll link one of their abilities to showcase how that might work and the many different ways we can build a class off the idea.
Magus -> Soulflayer, Poxbringer, Doomweaver
Magus mechanic is called Insanity. It has a base of 0 and a cap of 100. It decays at a rate of 5 per second outside of combat. At different break points of Insanity, you will gain Fanaticsms which cause your abilities to have specific negative effects which are labeled on the tooltips. At 60 Insanity you have Slaanesh Fanatacism; at 80, you have Nurgle Fanatcism; and at 90 you have Tzeentch Fanatacism.
This mechanic is inherently a negative feedback system. As such, magus abilities have a positive output modifier attached to them across the board. Abilities generate specific amounts of Insanity which is listed on the tooltip. Removal of Insanity is a part of each specialization and they go about it differently but doing so limits your output in a way specific to that specialization.
The entire mechanic uses the sacred numbers of the Chaos gods. Slaanesh is 6, Nurgle is 8, and Tzeentch is 9. Notice the breakpoints. Also the amount of Insanity a skill generates will be a multiplier of one of those 3 numbers based on the lore of chaos magic it comes from.
Marauder -> Bloodreaver, Nurgle (unnamed), Bladebringer
Marauder’s mechanic is renamed to Gifts of the Gods. This is the mutated arm /stance mechanics they had before with a handful of changes from AoR/RoR but it is functionally the same as what it was in our phase 2 testing outside of the addition of the corruption system.
First, no ability is locked out of any stance. You will be able to use every ability in every stance. You will not be able to nor need to switch stances by pressing a button for the stance. There are no cooldowns on stances. Instead, certain abilities will automatically shift you into one of the three stances when they are used. Other abilities gain additional effects based on the Gift you currently have active, these abilities do not auto-shift you.
Gift of Savagery – Gain 20% movement speed. All of your abilities apply 1 stack of Khorne Corruption to the caster, 1 stack of Khorne Corruption to the target, and 1 stack of Savagery to the target. At 5 stacks of Savagery, all stacks are dispelled and the target gains a stack of Blood-marked.
Gift of Pride – Gain 50% pushback immunity. All of your abilities apply 1 stack of Slaanesh Corruption to the caster, 1 stack of Slaanesh Corruption to the target, and 1 stack of Pride to the target. At 10 stacks of Pride, all stacks are dispelled and the target gains Sleepy.
Gift of Plague – Gain 20% lifetap. All of your abilities apply 1 stack of Nurgle Corruption to the caster, 1 stack of Nurgle Corruption to the target, and 1 stack of Plagued to the target.
Cultist -> Zealot, Hedon, Slaughterpriest
Cultists mechanic is called Blood Sacrifice. Your more powerful abilities will generate stacks of Blood Sacrifice on you rather than costing action points. Blood Sacrifice stacks up to 100 times and lasts 6 seconds. For the duration, you take 6% wounds + 90 ichor damage every second per stack. Cultists have a default 25% lifetap, meaning that they are healed for 25% of all the damage they deal.
This essentially means they they can use their health as a resource making them a self-lifetap class. Even the non-dps specs will need to apply damage spells or have access to additional healing in order to keep using their best abilities. Of course, by spamming powerful abilities you can make the incoming damage (since it is a dot) become higher than you can self-restore through the lifetap. There are tactics and other effects which can mitigate, or bypass the mechanic at times as well to give you some control of it.
Of course at any time you can also just stop using blood sacrificing abilities for 6 seconds to reset the stacks.