Yoakemono

Gin and Jinrou are two boys who make a formidable team in the mountains. Believing they can only move forward by going to the capital, Gin decides they should join the Shinsengumi. But the people they encounter there prove far tougher than they expected. Jinrou can smell something beastlike about some of them, including the Shinsengumi members, and they appear to possess unusual abilities. After Gin dies tragically, Jinrou resolves to grow stronger and take his place in the Shinsengumi.