He was the second in command of Lucky's pack, who spoke on behalf of the Pack Leader. He was tasked with enforcing the plan to have the subordinate Skinwalkers infiltrate human families by posing as pets. When the signal was given, the Skinwalkers would turn on their "owners" and convert them into new Skinwalkers.
Season 6
When Lucky began killing people who threatened his human family, the Packs chief superior (believed to be the Alpha Skinwalker) became angry that their plan was being jeopardized. The Pack Leader therefore ordered his right hand to have Mandy and Aiden kidnapped and have Lucky to turn them, unaware that Lucky was working with Sam and Dean who tracked the pack down to a warehouse.
Sam wanted to keep the Pack Leader alive in hopes he would lead them to the Alpha Skinwalker - which they could then capture and sell to Crowley in exchange for Sam's soul being returned. Dean, however, didn't want to risk the Pack Leader activating all his sleeper agents in town, nor did he want to sacrifice Mandy and her son. The brothers attacked the Skinwalkers with silver bullets and shoot the Pack Leader in the head.
With the Pack Leader dead, during the fight, Lucky tried to protect his family and morphed into his dog form to take on the Pack Leader's henchman. Instead of turning into his animal form himself, however, he pulled out a gun and shot Lucky with a silver bullet, wounding him. Before he could finish Lucky off, though, Dean shot him in the head with a silver bullet from his rifle, killing the Pack Leader's second in command.