Ruin would be a great character to pair with Kane. They both have strong military backgrounds and skills. Their combined combat abilities could make for some really intense and exciting scenes in a fanfiction. They could be on a mission together and use their different specialties to overcome obstacles.
It could be the way the crime is depicted or the setting of Chicago that makes it stand out. Maybe the characters or the plot twists are what's unique.
Yes, there might be. The Naruto fandom is huge and there are all kinds of fanfictions out there. Some fans might have created a fanfiction where Naruto is a Kane fan. You can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own.