Whichi - it was a nickname given to me from a friend way back in grade school, so I thought I'd use it on various game characters.
Masaharu - I hung out with this one Chinese girl (And by hang out, I mean I had to share a table with her in Study Hall) during high school. I was making a Monk for D&D 3.5, and I didn't feel like using the same name, so I asked her "if you had a baby boy, what would you name him?"
Mortran - A friend used that name for any and all dwarven melee characters. I upheld that tradition.