Manji is an infamous swordsman in feudal Japan who is known as the "Hundred Man Killer," as he has killed one hundred innocent men. However, there is something far more frightening than his ominous reputation: the fact that he is immortal. This is the handiwork of eight-hundred-year-old nun Yaobikuni, who placed bloodworms capable of healing almost any wound in Manji's body. To atone for his crimes, Manji resolves to kill one thousand evil men. Yaobikuni agrees to this proposal, saying that if he succeeds, she will undo his curse of immortality. Soon after this promise, Manji meets Rin Asano, a 16-year-old girl who requests Manji's assistance in killing those who slaughtered her parents. Initially reluctant, Manji refuses Rin's desperate plea. However, owing to her evident lack of strength, Manji changes his mind and agrees to protect Rin for four years. With this partnership set in stone, the two embark on a perilous journey of bloodshed, vengeance, and redemption, each to fulfill their own life's cause.

Your favourite teddy bear. That model kit that took so long to complete. The picture book you used to read over and over again. The shining stone you found that day in the park. Where do all your childhood's treasures go when you grow up? In this story, we meet fantastic creatures that gather all these little objects that fall into oblivion as they are forgotten by their owners when they step into adulthood. These creatures sneak into our world from a different dimension, and unseen by humans, they take all the ditched and forgotten "treasures" into their world. Here, they use their booty to build their own city, a fairy tale-like place called... Oblivion Island!

Recap of episodes 14-25.

Second season of .