The crimson shadow

Naruto, after being set up, had to leave Konoha. Though, they didn't know that that was their biggest mistake ever. War was laying on their door, and they weren't able to face it by themselves. Now, their only hope is 'The crimson Shadow', who was said to be even stronger than a kage. (Probably gonna be AU due to the manga, Post-war, no pairings decided yet.)