Christopher Heyerdahl

Christopher Heyerdahl (born September 18, 1963) is a Canadian actor who portrayed Alastair in Supernatural, the Wraith Todd in Stargate Atlantis, Sam in Van Helsing, "Swede" in Hell on Wheels, and Marcus in The Twilight Saga.

Supernatural · S4, E16

On the Head of a Pin

Castiel (Misha Collins) and Uriel (Robert Wisdom) capture Alastair (Christopher Heyerdahl), and ask Dean to torture him with skills he learned in Hell.
Supernatural · S4, E15

Death Takes a Holiday

Pamela (Traci Dinwiddie) sends the boys to the spiritual world when they find people cheating death. They must face Alastair (Christopher Heyerdahl), who is kidnapping the Reapers.
Smallville · S7, E6

Lara

Kara goes to Washington to look for her missing crystal, but is captured after she breaks into the lab. She's sedated with a truth serum that has kryptonite in it, which makes her relive a trip to Earth from the past. In this past trip she followed Lara, Clark's biological mother, to the Kent's farm. Clark saves Kara, but also ends up being affected by the serum when he burns it with his heat vision.
Smallville · S7, E8

Blue

Clark hears his mother's voice trapped in Kara's crystal, and releases her. She gives him Jor-El's ring made of Blue Kryptonite, which strips him of his powers.