Ikuseisou no Yoru wo Koe

Kyoushirou the mercenary is cursed with immortality after a battle with a strange man, and after years of wandering in loneliness, he finds himself out of place in modern day Japan. There, he discovers a young girl who is the descendant of his former enemy, Tokino. Though he desires revenge, can Tokino's kindness mend his tortured heart?