In manga and anime, sometimes characters have "four ears," yotsu-mimi 四つ耳, in the sense of having "two pairs" of ears, ni-tsui 二対, that are part of their body.
Generally, this happens when the artist adds a pair of cat ears, bunny ears, etc. on top of a human character's head that already has human ears or human-like ears.
Anime: Mairimashita! Iruma-kun 魔入りました！入間くん (Episode 10)
- Various characters in Iruma-kun have "elf ears," erufu-mimi エルフ耳 and "animal ears," kemomimi ケモミミ, although the latter is probably hair... in the same way that Kujo Jotaro's hat is probably hair.
Characters with four visible ears are few, as the lower ears are typically hidden behind hair.
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