Sanetoshi Watanabe
A peculiar woman who frequently shows up around Kanba and functions as one of the series' main antagonists. She's equipped with a custom slingshot that fires red projectiles capable of erasing memories, and she owns a penguin companion named Esmerelda—just like each of the Takakura siblings have their own.
There's an implication that she once had romantic feelings for Kanba. More significantly, her situation mirrors his in troubling ways: her brother Mario is trapped under the influence of a penguin hat identical to Himari's curse. To keep Mario alive, she's also hunting down Ringo's diary, putting her directly at odds with the main cast despite their shared predicament.
Content compiled by AnimeList.moe from publicly available sources.
