I'm going for a Batman: Arkham Origins Deathstroke. The Arrow and Injustice Deathstroke don't have gray hair exactly. Their hair are graying, but they're not gray yet.

@Patriarch, my version of Deathstroke didn't have any quarrel with the Teen Titans. I would have mentioned something as major in the bio. He might have had a couple of brawls with Nightwing and such, but no Teen Titans.

Also, my favorite character from Assault on Arkham is obviously The Joker. His line when he first sees Black Spider's decapitated head. Priceless.