Spawn + Iron Fist.
Spawn's big thing is having limited necroplasm, right? Malebolgia is very, VERY patient, and doesn't care what a Hellspawn does, because eventually they'll run out of power and be added to the horde.
So in my idea, Spawn stumbles onto K'un L'un, beats the dragon, and from that point out can call on the dragon chi indefinately and NEVER risk running out of necroplasm.
Malebolgia would not be pleased. (Bonus, Spawn heals himself properly. It would be like he never died..)