he was killed, so was like all demons but dreadlords
(back in warcraft all demons died. Then come wow aparently dreadlords would revive. Then come WoD all demons revived as long as they are outside of the twisting nether. Then come legion all demons only die if in the twisting nether, far away from argus, if near argus they could be saved using the power of argus itself, then ended once we killed argus)
but then when wod came along and added more demons to the "able to revive" list, illidan too was able to be revived.
also yeah, hes a guy who i used to really like but eventually started making weird conspiracies.. like for example in my sig, how "Azerite gear is random and i once got a piece with traits for the opposite faction, that also was missing a trait for my spec!"