[@Lmpkio]
Hmmm... perhaps. Vader is probably the more powerful Sith, although Set is far older. Set definitely doesn't trust Vader though, and Vader would almost certainly attempt to make Set teach him the Essence Transfer. After all, that ritual might allow him to be moved into a more functional body, one that doesn't require life support.

Edit: Also, is this Legends Vader, or Canon Vader? Cuz Legends Vader is a lot more powerful than the latter.