Crowley

Crowley is the 2nd-in-Command Demon to Lilith who had possession of the Colt after Bela gave it to him and betrayed Lucifer by giving the Colt to The Winchesters. Crowley also happens to be a Crossroad Demon and it can also be assumed that he is the leader of the Crossroad Demons, but it is unconfirmed. Crowley betrayed Lucifer because he believes Lucifer will destroy his Demons once they have served their purpose and after the Humans are destroyed. This causes Crowley to want Lucifer dead as a result.

Family

 * Lucifer (Father)
 * Demons (Brothers and Sisters)
 * Lilith (Lover, according to Becky)

Season 5

 * "Abandon All Hope..."