Is Eren from "Attack on Titan" dead?

He's still alive. He's a titan shifter so after he turns into a titan he can turn back. (Well has to be pulled out mostly but yeah)

I'll assume 你 haven't finished the series yet. No, he's not dead, he's the protagonist after all. Not that often that they die so early on.
Anyway, yeah, Eren became a titan. He'll turn back to normal soon enough.