|image= [[Image:Alastair demon.jpg|300px]]<br>[[Image:Alistair in 4.15 Death Takes A Holiday.jpg|300px]]
|actor= [http://www.imdb.com/name/nm0001679/ Mark Rolston] ([[4.09 I Know What You Did Last Summer|4.09]], [[4.10 Heaven
And Hell|4.10]])<br> [http://www.imdb.com/name/nm0382216/ Christopher Heyerdahl] ([[4.15 Death Takes A Holiday|4.15]], [[4.16 On The Head Of A Pin|4.16]], [[4.21 When The Levee Breaks|4.21]])
|dates= Unknown - 2009
|location= Deceased; Alastair is killed by Sam Winchester
|occupation= [[Demonology|White Eyed Demon]]
|episodes= [[4.09 I Know What You Did Last Summer]]<br>[[4.10 Heaven
And Hell]]<br>[[4.15 Death Takes A Holiday]]<br>[[4.16 On The Head Of A Pin]]<br>[[4.21 When The Levee Breaks]]
Alastair is a [[Demon|White-Eyed Demon]] (with white pupils and irises)<ref>[[4.09 I Know What You Did Last Summer]]</ref> who was at one point human. After being transformed into a demon, he somewhere along the way became responsible for torturing human souls in Hell; his ranking as a torturer remains vague. He is held in high esteem by many of his demon comrades. He possesses an extensive knowledge and awareness of the universe, having occult knowledge, usage of spells cast in [[Enochian]] as well as rituals.
Alastair was initially immune to Sam's psychic abilities <ref>[[4.09 I Know What You Did Last Summer]]</ref>, although, ironically, he is eventually killed by them.<ref name="four16">[[4.16 On
The Head Of A Pin]]</ref>His durability seems to exceed that of most demons', as Ruby's Knife, a weapon that can kill demons, could greatly damage him but could never destroy him.<ref>[[4.09 I Know What You Did Last Summer]]</ref><ref name="four16" />
As a torturer, he is an expert interrogator In that regard, according to Castiel, he had an exceptionally strong will, allowing him to sustain himself while being tortured.<ref name="four16" /> Meg was an apprentice of him before his death.<ref name="six10">[[6.10 Caged Heat]]</ref> He tortured both [[Dean]] and [[John Winchester]], and in both instances offered to end the torment if they would become torturers themselves. Alastair reveals that the first seal was broken when Dean accepted this offer.
He also can send an angel back to Heaven by expelling it from its vessel.<ref>[[4.10 Heaven
And Hell]]</ref><ref name="four16" /> Alastair has shown to be resistant to an angel's power of exorcism.<ref>[[4.10 Heaven And Hell]]</ref> He possess knowledge of the Four Horsemen of the Apocalypse and has demonstrated power to overwhelm a reaper.<ref>[[4.15 Death Takes A Holiday]]</ref>
Sam stabs the demon with [[Ruby's Knife]], but he is unharmed. Sam and Dean escape by jumping out the church window.
Alastair appears again to Ruby at a crossroads where she tries to make a deal with him: giving him Anna Milton in exchange for allowing her and the Winchesters to go free. He then makes her a counter offer, capturing and torturing her with her knife. He later has a showdown with [[Castiel]] and [[Uriel]] in which he overpowers Castiel, but is distracted from harming him by an attack from Dean. The fight is interrupted when Anna reacquires her [[Grace]] from Uriel, she and Alastair then both disappear in a flash of bright light with Alastair leaving behind only Ruby's Knife.
[[File:Alistair with Death's weapon.Jpg|300px|thumb|left|Alastair in his New Meatsuit.]]
===[[4.15 Death Takes
Alastair is attempting to break one of [[The 66 Seals]] by killing two reapers under a solstice moon. He confronts Dean and Sam in a cemetery, and injures Dean, but Sam is resistant to his powers and fights back. Alastair reveals that while his [[meatsuit]] was destroyed by [[Anna]], he himself survived. He flees when Sam tries to exorcise him with his powers and later returns in yet another meatsuit. When the boys become non-corporeal, and therefore subject to ghostly weaknesses, they track Alastair down at a funeral home and he traps them with an iron chain. He kills one reaper, but the boys rescue [[Tessa]]. Later as he confronts Dean, Alastair is captured by Castiel.
The Head Of A Pin]]===
[[image:Supernatural-04x16-OnTheHeadOfAPin.jpg|300px|right|thumb|Alastair being tortured by Dean.]]
Alastair is captured by Castiel and Uriel and imprisoned in a [[devil's trap]], but he refuses to tell them anything about the slain angels. Dean is recruited as an interrogator because he was formerly Alastair's student during his time in Hell. After extensive torture, Alastair breaks free Uriel having sabotaged the Devil's Trap to prevent his role in the angelic deaths being revealed. He almost kills Dean, but is stopped by Castiel, who throws Ruby's knife and embeds it in Alastair's chest. Alastair pulls the knife out and fights Castiel. He manages to trap him against a pillar, and admits that while he is unable to kill the angel, he will send him back to Heaven. Alastair begins to chant, but he is stopped by Sam, who has become strong enough to overpower him with ease. Sam forces Alastair to talk, then kills him via his abilities.
The Levee Breaks]]===
While withdrawing from the [[Demon Blood]], Sam hallucinates that he is tortured by Alastair.