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Aoba's All-Mate, an all purpose computer that can take various forms. Aoba considers him a dear companion and personally maintains him. They've been together for as long as Aoba can remember. His breed is a Japanese Spitz.

[Spoiler: For some unknown reason, he takes human form within Rhyme.]

[Spoiler: Ren is the main partner of the secret, unlockable route which is also the true route of the story.]