Nine Tailed System NTS

Marco, one of the abnormal trio(With Gabriel in Fanfiction: Hail the Ant King and Billy in WIP), lived his life peacefully, until he and Billy accidentally sent their friend Gabriel to another world.
When they received a mysterious letter from him, they got enraged and picked a random house to suicide, promising to kick Gabriel's ass when he will meet him, Marco leaves the world with a special gift...
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Fanfiction in Monster Girl Quest.