During your exile to the Seirai Island, where all the monster are lurking and full of Abyssal Monsters, you are badly injured and tired. Then, you found a cave and rush into a cave for safety.... But.. you found an Oni.. A fatal wounded woman who lost her right arm and a Oni Horns and barely breathing. She looks like she was corrupted but the corruption in her was weakened and she managed to control her body.. You, also an Oni kind, rush to her to see her conditions..