Ability Sets

What are Ability Sets?
A Spirit has an Ability Set which is determined by the Elemental type of the Spirit and the kind of player ability that the Spirit would provide your Champion. For example, one Spirit may have an Ability Set defined as Ice Offense. This would mean that this Spirit grants the Champion an offensive Ice attack, which would be weak against monsters of the Element Nature. There are a few kinds of abilities : Offense, Defense, Healer, and Balance.

The 5 abilities
Auto-attack: tap an enemy and deliver the hurt

Mobility: either a jump or a blink, depending on class

Channeled: tap and hold while aiming to channel or charge this ability

AOE: double-tap your own character to activate this area attack around your character

Ultimate: when charged, press the big button and watch stuff happen!

Spirits in ability slots
Auto-attack: your natural attacks deliver a certain amount of raw damage. Adding any spirit to this slot changes the damage type to the element of the selected spirit, while also adding more damage, depending on the level and tier of the spirit. Don't forget to use the right element against the right enemies!

Mobility: your mobility moves gain an effect from the spirit. This effect does not depend on the ability set of the spirit but rather more on the element of the spirit.

Channeled: defensive spirits in the channeled ability slot usually provide an aoe, either directional or circular. Elemental damage increase depends on the level and tier of the spirit. Using an offensive spirit will result in more directly targeted effects, some with a splash effect.

AOE: defensive spirits in the AOE slot, creates a shield for sorcerers and a totem for warriors. The totem effects vary a lot, so make sure to experiment! The offensive spirits give sorcerers either an AOE effect or an AOE explosion of sorts, while warriors get an added elemental damage bonus to their attacks for a while.

Ultimate: For warriors, these effects vary wildly, ranging from 100% self-heal to different types of AOEs. Sorcerers tend to have some hefty AOE damage effects when using offensive spirits but can trade some damage for other effects by using defensive spirits.

Discussion
It seems that the wide range of different ability effects supplies gamers with more tools to tailor their character into either solo or group gaming. These many effects can seem quite overwhelming at first, but it seems that for warriors, some of the totem effects will be really strong in groups, the same as certain ultimate abilities among sorcerers, meaning that instead of being 4 individually strong players in the dungeon, they can add more power to each other, thus making the team more effective.