Blade of the Immortal
無限の住人 (original)
Edo, an era of warriors. There lived an immortal man, the Slayer of Hundreds, 'Manji.' He meets Rin, who has sworn vengeance for her parents. Rin's grudge is against a group of swordmasters – Ittou-ryu. She asks Manji to be her bodyguard on her journey. He refuses, but then sees his late sister in Rin. So began the violent struggle that would bring even the immortal Manji to his knees.
Starring Rina Sato, Tomokazu Seki, Daisuke Namikawa, Hirofumi Nojima, Katsuyuki Konishi, Kazuya Nakai, Mamiko Noto, Masashi Ebara, Megumi Toyoguchi, Shin-ichiro Miki
It's a action & adventure and animation show, and has a rating of 6.7 out of 10 from Imdb which is usually fine for this kind of show.
Watch it here
Not found streaming from United States.