[Help me Find]

looking for a manhwa, and as far as i can remember, he was a demon king, or of equal standing, he was either killed or sealed, and then later woke up, or was reborn in a room of (if i remember right) what was once his castle, he a little bit later, like within a few chapters of the beginning gets a friend/pet dragon whom is/was the child of a older dragon who was originally good friends with MC before MC was killed/sealed, i doubt anything will actually come out of this, it's pretty vague, but if i gotta try anyways

Edit: as an additional question besides the original, is Cultivator VS Superhero any good?