Battle Spirits [Re] Zekkai no Kuu

Keio 3, Hinomoto, Eito. As the Bakumatsu throws Japan into turmoil, young Kuu Bashin dreams of becoming stronger through Standard Battle Spirits. His world changes when he encounters Ajara Zetsu, a wandering samurai and formidable Eternal Battler pursued by anti-shogunate forces. As the worlds of Standard and Eternal Battle collide, Kuu is pulled into Zetsu's journey-and sets history in motion.

(Source: Crunchyroll)