Mugen no Juunin: Immortal S01

Mangi is an immortal swordsman who has been cursed with eternal life and is tired of the deaths that have occurred during this period. He has no skills other than killing and therefore concocts a plan to reverse his fate: he must kill 100 evil humans for every good human he has killed. The sorcerer who cast this curse on Mangi agrees with this plan and Mangi begins his journey to kill 1,000 evil humans. On his journey, he meets a young girl named Rin who has her own reason for revenge and is seeking a school of swordsmanship that killed her family. Rin and Mangi travel together, each hoping to find some kind of peace. Along the way, they face many enemies. Rin and Mangi are almost always under attack and must learn to find their way to life and not succumb to revenge.