I wouldn't call it "teaming up" in any way. It's not as if Jasonafex is actively working on the project with him or anything. He was just desperate to get attention to his buggy mess of a "game" so he did cameos with other people.
As a showcase of how grateful Jasonafex is to these people, Vitki added Vergence as a full on interactive character from the start.
Jasonafex added Vitki's OC into a debug room you have to go out of your way to find.
I'm not even sure if he's still in the new Unreal Engine version, so this whole thing is moot anyway, if that's the case. He's not.
