Threads of Fire and Flame

I found the hundred themes challenge and I had ideas, so, what if Ryuuji was son of both his cannon father and Karura? What if Shiro Fujimoto lived?
Add in variables, remove others, and have Yukio and Rin get a healthy relationship and some mama Shura later on, and big sis Izumo.

I will work on the description later, but for now just enjoy this. I will cross post this on Ao3 later.