Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Help with modding Source Vampirism?

Looks like thats a hard-coded effect. If you want to change it you will have to use the script calls that alter Source Points for a character. CharacterAddSourcePoints and CharacterGetSourcePoints. You will also want to put a CanGiveSP check in the TargetConditions field so the skill can't be used on targets without SP.