Samurai 8: Hachimaruden

As the galaxy nears the end of its existence, it won't survive for more than a century. A samurai receives a mission to save all the planets and its inhabitants by finding Pandora's Box. The warrior god Fudo Myoo places a secret inside of it that will save the world. However, in order to open it, they have to find the seven keys and Hachimaru, a weak child who's needed medical assistance since birth might have something to do with it.

(Source: YonkouProductions)