|You think his friends just called him Yellow Eyes? He had a name.|
This article is about a canonical individual whose real name is unknown, and is known only by a conjectural title, nickname or alias.
Following Sam Winchester's nearly successful attempt to exorcise him from his previous, brief vessel, Alastair possesses this man to go ahead with his plan to kill two Reapers in order to break one of the 66 Seals. Although Alastair succeeds in killing one, the Winchesters manage to save the other, Tessa, and Alastair and his vessel are captured by angels led by Castiel.
Alastair, still possessing this man, is held in a devil's trap in an old warehouse in Cheyenne, Wyoming where the angels try to break him for information on how Lilith is killing their fellow angels. When that fails, they bring in Dean Winchester to use the knowledge of torture he got from Alastair to try to break him. Despite Dean's best efforts and doing severe damage to his vessel, Alastair doesn't break and escapes with the help of Uriel. Despite Castiel's best efforts, Alastair proves unable to be stopped until Sam arrives after finding them with the help of Ruby. Sam's psychic powers prove too much for Alastair and he quickly breaks under the torture of them. Sam uses them to kill Alastair and if the man was still alive at that point, he died with the demon due to the extreme damage his body took from the torture.
Sam hallucinates Alastair torturing him while detoxing from demon blood and in the hallucination, Alastair is still possessing this man.
While torturing Alastair, Dean inflicted a profusion of mortal injuries upon this man's body. When Sam killed Alastair, the man instantly died of the injuries Dean had inflicted upon his body.