Alastair

Alastair eventually leaves Hell, and attempts to capture Anna Milton, a fallen angel who can hear the conversations of other angels. Sam and Dean interfere, and, although Alastair is shown to be superior to Sam's abilities and highly resistant to Ruby's demon-killing knife, the brothers escape with Anna. Alastair is later tricked into capturing Ruby, whom he then tortures to get her to "reveal" where Anna is. When he goes to collect her, he is stopped by Castiel and Uriel. Alastair and his demon minions face off against the angels, and he proves to be more powerful. However, Alastair vanishes in the flash generated by Anna being restored to her angelic true form. However, he returns in "Death Takes a Holiday" in a new body, kidnapping Reapers in order to break another seal. He is stopped by Sam and Dean, and is eventually captured by Castiel. Tortured for information by Dean on Castiel's orders in "On The Head Of A Pin", he refuses to break. Escaping from the Devil's Trap with assistance from Uriel, he attempts to kill Dean and send Castiel back to heaven, but Sam stops him. Using his abilities, he tortures Alastair for the information about the angel slayings, learning that the demon has no knowledge about whom is doing it, and eventually kills Alastair. In "When the Levee Breaks," Alistair appears to Sam as a hallucination caused by withdrawal from demon blood.