Samurai Deeper Kyo

In the year 1600, during the battle of Sekigahara, warriors Kyoshiro Mibu and "Demon Eyes" Kyo - the legendary slayer of a thousand men - engaged in fierce combat. Both men disappeared when a meteor crashed in the battlegrounds. Four years later, Kyoshiro is spotted on a rural highway, acting as a traveling medicine salesman. He is captured by the female bounty hunter Yuya Shiina when she discovers that deep inside him is the dormant personality of "Demon Eyes" Kyo himself.

(Source: Anime News Network)