[@Ojo chan 42]

I like the character concept, but I want to give some suggestions.

So you mention the mafia. The mafia is more of an east-coast thing in the usa, and it's pretty much all Italian types over the age of 40. If you want to be from the west coast, you should think more of him being in a gang and involved in drug trafficking, human trafficking, or smuggling weapons. He'd have a lot more assassination targets down in LA or San Diego. San Francisco is really not as much that kind of town. You might get away with San Jose. 

Next, tall, young, blonde, blue-eyed French guys don't do criminal organizations. They just... don't. I mean, they could, but probably not at 16. Your character would pretty much have to be black or Mexican or some poorly educated, angry, brown type. Sorry, but that's WAY more likely. If you want to be some rich white kid in the Illuminati, sure. That would fit. He would probably have other people doing his shooting.

Other places he could have learned to shoot would be the military or police academy, or maybe his family was involved in those. Maybe he watched too many movies and frequented the local gun club with an unhealthy obsession and is considering snapping and killing a lot of people. I don't know. Very few humans in these times would have been around to have personally fought in the Nightwars.

I'm not sure about how the world will be in 2100, but in 2016, 22 year olds still live with their moms and can't get a job. Most haven't finished their primary schooling by 22. Accomplishment and respect don't really happen until 35+, not to mention having killed people. I think you may need to make him older, or make him much less independent. 

For what it looks like you want to do, you should say he's Canadian, or fled from a bad home in New York City or somewhere east coast. Maybe he used to work for Soldier for a few years and quit. Maybe he really did kill some people when he was a teenager and now they want revenge. Maybe he killed some mafia guys or cult members and didn't realize it. They probably would have to attack his home or something. I don't know. You can come up with stuff.