I'm not entirely sure. I know he was rumoured to have been trapped within the Shield of the Hidden Lord due to the Spellplague, but death or entrapment have usually been little more than a temporary inconvenience to a deity (or demi-god). In the context of BG3, seems somewhat moot, given this one's name is Raphael, as revealed in the stream (doesn't mean conclusively it isn't Gargauth...he is referred to as the Hidden Lord after all). Still, it seems unlikely now that this is Gargauth (a proxy or follower at best, if connected to Gargauth in any fashion).
