Blade of the Immortal, Volume 1: Blood of a Thousand (Blade of the Immortal #0-2)

To end his eternal suffering, he must slay one thousand enemies! Manji, a ronin warrior of feudal Japan, has been cursed with immortality. To rid himself of this curse and end his life of misery, he must slay one thousand evil men! His quest begins when a young girl seeks his help in taking revenge on her parents' killers... and his quest won't end until the blood of a thousand has spilled!