Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Skill like Inner Demon?

I saw one other post about this but it got no replies. How would I go about creating a skill that, when activated, gives the character access to a set of new skills for a number of turns? I saw that Inner Demon uses a skill property called "INNER_DEMON" I think, which I assume is what gives the new skills? How would I create something like this for skills I've made?