Phil would ask/know. But I think it depends on the gods. The Magi are demigods, and we know what happens to their power. Orihalcum nearby could absorb some of it, for some it probably goes back and is reincorporated into the celestial plane, and we have Liches, so some probably immediately reincarnate (if something like Phil doesn’t stop them). Despite magic being energy dense, it also seems generally inert, so I doubt many explode when they die except as a death curse lmao- my bet is if they don’t have specific conditions like the Magi, the magic just sits there, slooowly dissipating like dry ice until someone compatible with it claims it, it is absorbed into something else (cursed gear set anyone?) or eventually fades away.