Alastair

Alastair was the demon who tortured in hell and responsible for Dean break first seal and give begins to doomsday.

He also is secondary antagonist who appeared in series horror Supernatural.

In Supernatural
Alastair was an human who turned an demon some years later Alastair was responsible for torture of John Winchester for an century would be equivalent the to one year on earth until John escape after what your sons open the hell gate after kill Azazel, after Dean go for the hell what Alastair torture Dean for some years until he accept and break the seal after torture of a soul innocent in hell after of leave from hell with help of Castiel without what he knew. In episode I Know What You Did Last Summer and Heaven and Hell, Alastair with orders of Lilith, tries kidnap the fallen angel Anna Milton what could talk of angels, arriving in house he fight against the Winchesters what them escape after he find Ruby what her is kidnapped for Alastair and tortured what she the takes until Dean and Sam Winchester he fight against Castiel who takes advantage against Castiel after Anna recorvers your grace what she pulverize Alastair and his vessel.

In episode Death Takes Holiday, Alastair together his demons, kidnapped very reapers and including Tessa for cause this came many ghost after Sam and Dean Winchester decide investigate with a medium withal name of Pamela who help them doing them turned ghost for some minutes arriving, Sam and Dean Winchester discover in an place who all was work of demons after them fight against Alastair and his demons, the Alastair ends capturing soul of Winchester brothers who them escape of returning for your body with Pamela dead for an demon after Alastair go behind of Dean only he be captured for Castiel.

In episode  On the Head of a Pin, Alastair refuse talk so Uriel and Castiel decide recruit Dean Winchester for do talk about the death of angels, Dean talk with Castiel after Dean torture Alastair what the same resist the torture of Dean, Uriel liberted Alastair of trap him if break from chains for attack Dean after he fight against Castiel what almost kill when Sam arrive and use his psychic powers against Alastair end killing he.

In episode  When the Levee Breaks, Dean imprisoned Sam for cause of his blood demon after Sam begins see hallucination as the of Dean and Alastair & until more