The Main.pak [1] holds a lot of scripts dealing with spell behavior, and script language is pretty basic.
The problem is that spells/abilities aren't scripted
They are described by Public\Main\Stats\Generated\Data\SkillData.txt and the SkillData.xlsm files.
You need to pick a "template" or type for each ability, which determines the way it works. You can specify a bunch of parameters that change the behavior of the ability, but they have fixed functionality by design and AFAIK you cannot extend them beyond those.
eg. skills with a SkillType of Summon can only summon entities, they cannot fire projectiles or do AoE-s or any other stuff; if what you want is not available in any of the SkillType templates, you can't do it.
