

You can also define who can be the target like a single target (enemy, self, friendly but not self, friendly) or group AoE enemy, AoE friendly (for example for health or buff abilities.

You can also use reagent so your ability can check if you have some item in your backpack, like in order to use some Meteor Shower maybe you will need some fire potion or scroll, should it be consumed or not. You can define which skill can be leveled if you will use that ability, is it passive, what is the cost, it can be mana, health, like sacrifice health to refresh mana or use a new stat called stamina.

They are responsible for conditions like who is the target, what attributes will be taken into account to calculate the output like friendly effect has 100% success rate, applying slow can have 50%, but damage physical or magical will be based on caster/target physical/magical damage/resistance parameters.
