Other than a few flashback, we haven't really seen much of Dean's Purgatory savior Benny, but the latest episode shines a light on this vampire's motives for getting back into the world.
Benny has an agenda and it's to avenge the human love that his maker and nest took from him. He was part of a group of vampire pirates that bled the rich and let the sea wash away their victims. That was until he met free spirited Amelia who was traveling the world.
Benny ends up running away with her and his maker tracks him down, kills him and vows to drain Amelia. His first business when he came back was to avenge her death by killing his maker. A nasty fight leaves him injured and he calls Dean in to help him out.
Dean ends up helping him, but Benny finds out that his maker didn't kill his love, but turned into a vampire and has now become second in command. She helps Benny have the tools necessary to kill his maker, but when its all said and done she's no longer the free spirit.
Dean ends up cutting her head off and Benny is left with a crisis of conscience and purpose. Benny isn't like most vampires and only drinks from donated blood and not from live humans. He's also not evil and Dean respects him. We find out that even though Benny considered Cas a liability, he still saved his life.
I really ended up liking Benny's character by the end of the episode and felt sorry for him.