[So, this is Hell. Makes perfect sense. Levi doesn't remember dying, but that hardly matters now. Here he is. If it isn't Hell, then it's some realm that Eren no doubt controls, where the dead don't die, and all he does is lie around and nap. Also fabulous.

[Then it isn't just that putting Eren down would be unnecessary here - it would be impossible.]

That's it. You haven't met anyone else?

[There's a name or two he's hoping to hear, maybe - so sue him.]

You say he's dead, but you imply that the same can't be said for the rest of us. Too easy an explanation, I guess.