Is the Cerebrate player-character in Brood War still alive?
Originally I thought you (Terran PC) killed the PC Cerebrate in one of the Blizzard downloadable maps, or non-canon expansions. However, while digging, I found this interview: BlizzCon 2007 StarCraft Lore Panel.
The relevant quote from Chris Metzen:
Metzen: “…since Brood War there’s only one mind controlling the Zerg (as far as anyone knows). After Brood War she whacked out all the (remaining) cerebrates, so as far as anyone knows she is in sole control of the swarm. But that sure is an interesting theme wink wink” (bold emphasis mine).
Seems harsh to kill your personal Cerebrate, but that's the Queen B of the Universe for you, I suppose.