|Actor|| Nathan Dales|
George Klimovich (Young Oskar)
|Dates||c. 1705 - 2015 (killed by Rowena)|
|Episode(s)|| 10.22 The Prisoner|
10.23 Brother's Keeper
If you can fry up a decent burger you can get work anywhere. I'm dying to head to Asia. It's just a dream, you know?
– Oskar/Seth, 10.22 The Prisoner
Oskar was the son of a peasant Polish family, who hundreds of years ago gave aid and shelter to Rowena. Over time Rowena grew to love Oskar, and upon learning that he was terminally ill, decided to give the family the gift for their kindness and cured Oskar with a spell, as well as casting a second spell that would take root when Oskar became fully grown, making him immortal. Oskar would travel all over the world during this time, and by 2015 had settled somewhere in the United States as a fry cook under the name Seth.
After Oskar serves a customer some coffee, he turns to place the coffee pot down when he hears a sudden noise and turns around to see Crowley standing in the middle of the room, with every other occupant of the diner unconscious on the floor. Crowley telekinetically immobilizes Oskar, and begins telling him the story of an old witch and a Polish family, revealing that he knows Rowena loved him and gave him the gift of immortality.
Crowley takes Oskar with him to Castiel and Rowena when he delivers the ingredients. When he reveals Oskar to Rowena, she tells him the act is a cruel new low for Crowley, to which he replies that it is only cruel if she actually goes through with it. A visibly shaken Rowena tells Oskar to come and give her a hug, as he does, she promises him nobody will be hurt, telling him goodbye, before she stabs him the neck and spills his blood into the bowl.
After Gavin returns to his own time to restore the fate of his lover, Fiona Duncan, Crowley wanted to know why Rowena stopped him from taking Gavin away to prevent that from happening. She told him that it was payback for what he made her do to Oskar to remove the Mark of Cain from Dean, so Crowley can witness the loss of someone he loves.