Jackson was a demon that work for the crossroad demonGuy.
Background
Jackson worked with Guy and helped Guy collect early on his deals for people's souls. At the same time he was also reporting back to Crowley since Guy was using a loophole to collect early. Although he gets noticed by Dean when he attempts to kill the CEO's wife who made a deal with Guy. He appears again when Guy is trapped inside a devil's trap and breaks it for him. As he is choking Sam telekineticly, he is stabbed from behind by Becky with Ruby's knife.