Fics like Demon's Sepulchre

The Gasai Yuno of the Third World—this Gasai-san who has been nothing but kind toward him—is not a monster. And if she receives the memories of the Gasai Yuno of the First World—that Gasai girl who has been nothing but hostile toward him—this Gasai-san will be tainted by her darkness. This Gasai-san will become the monster he swore to slay. (but of course, there's no way he could possibly care—right?)

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