I've had people balk at me for giving principal characters names that started with the same letter. >> Personally, I love it when characters have similar names because it's an added little dash of realism and vitality to a world. It's just hard to pull off well.

Mmm... Looking at what you've said about the story, I'd guess Big Jude's your most likely nickname candidate. He's out hunting bounties across the dimensions. I'd guess that means he needs cover personas and has a reputation. Either of those lends itself well to creating a nickname. Is he known for any particular feat or skill?