Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Mods Using Mods to Change Stats, Skills, etc.

You don't necessarily have to use anything as a base, just create your own mod in the editor, set the Main mod as a data & mod dependency (important!).

Stats are not editable directly in the editor, you have to create your own skill definition file (Data\Public\%yourMod%\Stats\Generated\Data\SkillData.txt) and fill it with the skill changes you want to make.
To change Divine Light, copy the 'new entry "Cone_DivineLight"' section from the Main mods SkillData.txt and customize it to your liking.