Austin Reynolds is the son of serial killer Tommy Tolliver.
Overview
Austin is a 12 years old boy who lives in Ohio with his mother, while he and his father are estranged. He owns a Facebook page, from which Sam Winchester uses to track his status.
After Cain murders Leon and Tommy, he goes after Austin. Sam, Dean and Castiel manage to get to him first and send him away to safety. They use an illusion spell to trick Cain into coming to a barn where the fake Austin is. He and Dean then get into a fight.