[quote=@Gentlemanvaultboy]
I'm thinking a world noble bought a slave that looked a lot like him for the novelty, and then a golden opportunity presented itself.
[/quote]

Eh. I still can't see the other World Nobles letting him get away with killing one of them. Remember what happened when Luffy just [i]punched[/i] one? I can see a World Noble buying a slave that looked like him just for fun (hell, one of them was going to buy Keimi just to watch her outrun a pack of piranhas in his fish tank), what I don't see happening is people not knowing he's a slave (slave get branded, so if he managed to swap places with his owner then I can't see him hiding that mark forever. Especial if he looked like his master and they needed to confirm who was who). I didn't see much point to putting a lot of thought into his backstory (since I already put quite a lot into Johnathan's mom) since I don't expect him to appear in the RP