Well for starters we don't like characters that are trying really hard to be total cool dark-themed guys, but, really, they're just trying to do good. Or something like that. 

No offense, but it seems like you've done everything you can to make him a psychopath, and that's not something we're looking for (per say, you can be twisted but it's a bit of a grey area. My advise is avoid it and go for something a bit more acceptable). I have to say, combat wise, he's [b]very[/b] balanced and needless to say that doesn't really have to change too much. 

Just ramp down the psycho-part, since there's no way Konohagakure will openly accept a brutal known murderer, traitor and thief of artifacts and just go ''hm, what [i]could[/i] go wrong? [i]Nearly everything..[/i] guess we'll take him in.'' Realistically, they'd arrest him and hand him over to Kirigakure, sword and all. 

If you [i]truly[/i] want to fit in well with the crew you should take a look at other characters and see what would fit well with them. Tip: it's not a 24 year old psychopath chunin artifact stealing guy. I'm sorry if I sound harsh or anything, but roleplaying a character like that would be bad not only for the RP (it can cause stand stills) but also for you, since they're generally not interesting to RP what so ever. They just look flashy and cool, but most of the time you're in combat you're not gonna be mercilessly beheading people left and right.