So, because [i]most[/i] of the job has been made, here's my review: 

-To start off you have a 24 year old guy from Kiri. Are you sure you want him to be 24? He's quite far off the age group of the chuunin of the RP. That won't help in interaction if we're being realistic. 

-His personality is extremely short. The little content we got is: He's anti-social, meaning characters won't like him very much and he'll interact poorly which kills the purpose of RP'ing. Also the maniacal laughing side is cliché as all hell tbh but to each their own. 

-The history, ah la la... To start off you could cut it into two or three paragraphs to ease it for the reader. You go off by introducing him as a sociopath who is incapable of being the least bit intriguing for other characters, so ehhhh. Moving on, he then gets obsessed over death and Zabuza and w/e, sure. The problem emerges when he starts killing random people and steals an artifact from a GOVERNMENT. Not only is this feat extremely complicated and barely possible for a chuunin alone in this modern era, but now he's a missing-nin. Now I'm willing to accept he could sneak past some stupid guards, but now he's a wanted man and there's no way in hell Konoha would accept him as a chuunin. Fujitora would simply murder him for bonus cash, and quite easily too. So no, having this massive sword stolen is a no-go, and neither is being a rogue ninja wanted by a massive country. We're at an era of peace, we're not going to let some weirdo break stability. 

-He's compared to Zabuza, who was a Jonin ranked guy and pretty good at what he did. There's no way your character could be as notorious at his current level to be perfectly honest. Not without reaching the ranks of Jonin. I can't accept this part either. 

-As said before, Executioner sword is denied because of the context. Find a better one and I may reconsider, but it'd still be very improbable considering it belongs to Kiri. 

-Your second sword is alright, however a year and a half to make it? You do know IRL it doesn't take that long to make a high quality sword right? And here it's super ninja magic land, so if in Kill Bill a guy could be the greatest sword in the world in one month, there's no reason for this one to take almost 2 years lol. That's just silly. 

-Techniques are alright. Just don't powerplay the silent killing. 

-Listen to Partisan for the coding. We like our CS' clean. 

[b]Conclusion:[/b] I suggest re-working the character, his personality and history. He just seems like a bland psychopath my Jonin would wreck after your first post just for existing. Really. If you need guidance, don't hesitate to ask but I won't accept it as it is.