I have read about the duplications of this chap, apparently mostly outside of whiterun, however as i broke into the above fort ... he walzed in after me and proceeded on through. From the sounds of fighting and pissed off bandits ... i dont think he made it lol

Is it normal for him to spawn elsewhere?

I saw Mr. Letrush and his twin brother randomly runnin in the snow up by Dawnstar one time. It was a nasty blizzard, and I was unable to follow them because I lost sight of them. I wanted to see what they were up too, since Maven Blackbriar was supposed to have dealt with him or something.

Yeah, I saw him around Dawnstar once too. I ended up setting him non-essential and killing his five clones. Amusingly, they all had drastically different loot on their bodies.

That guy is an otherworldly mutant. I wouldn't mess with him, he's probably Molag Bal incarnated.