Who is the deamon that killed dean?

Actually Lilith and the hellhounds did it both.

Dean made a deal to sell his soul for Sam's life and the demon who held that deal was Lilith which means that in order to get out of his deal someone had to kill Lilith.

In no rest for the wicked they went after her but while running away from the hellhounds that were going to kill Dean. they got stuck in a room with what they thought was Ruby but was actually Lilith possessing the same body Ruby was first possessing.

Lilith sent the hellhounds after him and they killed Dean. So it were the hellhounds that killed him, but Lilith held his deal so they both sort of did it.

And Castiel is an angel, he wasn't around till the 4 season after Dean already died.

Lilith, and just so u know, Castiel(not Castio) is an angel, not a demon ;)

it was lilith and actually it wasnt really a deamon it was hell hounds that killed dean

It was lileth. she's a creepy little bitch! and the angels name is castiel. well she didn't kill him personally but she did set the hellhounds on him!

Lilith killed Dean

IT WAS LILTH THAT KILLED DEAN

well dean made a deal with a demon and he only had 1 jaar to live so lilith and the hellhounds killed him when it was his time

it was lilith but in ruby's body..

I cant really remember but i belive it was either lilith of alistar but im pretty sure lilith lol

I forgot that bitch's name but it wasn't Lillith.

lilith and her hell hounds

If u want to get technical about it Lilith opened the door and let them in but the hell hounds riped that beautiful body to shreds. :(

The name of the demon who killed Dean is Lilith and some Hellhounds.

I thought it was alister?

LILITH