Sasafune is a mermaid who shows up in episode 8 when Takashi visits an inn with some buddies for a study session. She and the inn's owner, Chizu Sakanaka, go way back—they knew each other when Chizu was just a kid. Sasafune had convinced herself that Chizu had exploited her for her mermaid blood, which supposedly grants immortality to anyone who drinks it.
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