RED

Set in nineteenth-century America, Red is the last living survivor of a Native American tribe that was slaughtered by white men. On a long journey in search of revenge, he travels with Iero Ito, a samurai who ran away to America after being defeated in the Seinan civil war, and Ann, a mysterious prostitute. The bonds of friendship between the three are touching. Although it is all fiction, the story seems very real as it is based on actual battles between US troops, Apaches and other tribes. — Description from AniList community (anilist.co).