Originally Posted by Nicottia
Originally Posted by Gray Ghost
Does he canonically always come back to life or does he only come back if you do certain things?

Always, first 10minutes into Throne of Bhaal he is brought back and you can only do one thing: bring him back via sacrificing a miniscule part of your Bhaalspawn essence to do that, or have Imoen do it (she volunteers too). He is brought back as a some sort ghostly being (which is why his portrait in game has shining eyes and a glow around his whole person). Thing is, you canonically have no choice but to bring him back cause he holds vital information to you and he is basically sort of blackmailing you: "bring me back and I will tell you what you need to know, but if you refuse, I go na na na". Then the next choice is: do you keep him around (as a companion) or tell him to fuck off, so he literally just disappears from the game entirely.

And I think Larian went the 'fuck off' route with him. Abdel Adrian(the 'canon' Gorion's Ward from the books) had him stick around for a bit.

There are still some inconsistencies even if Sarevok doesn't join Charname or change alignment. In ToB he desperately wants to be resurrected ("You do not fear death? You should. I know what it is like. I had to scratch, claw, and plead my way back into the land of the living."), while in BG3 his diary says something along the lines of "I was cruelly resurrected against my will" (can't find the exact text right now but it's in the Temple of Bhaal).

When talking to Viconia in ToB he says "When Bhaal held sway over my soul, I reveled in the bloody carnage I wrought. But my will was not my own. As captivating as your dominance might be, Viconia, I will not surrender my being to the whims of another again... be they god or drow" and calls Bhaal a fool. Hardly a zealous follower.

There are explanations for how he would end up like that in BG3, I guess, but it's quite anticlimatic regardless of his potential alignment change. But then again I'm only taking BG1/BG2 into consideration, I'm trying to ignore whatever WotD canonized later.
Like others already said it would have been easier if he was called "Echo of Sarevok" like the others, a ghost of only the parts of him that Bhaal knew and had control over.