Mistress of the Scarlet Devil Mansion. 500 years old. Possesses charisma (or rather, 'baby-isma'). She refuses to acknowledge the relationship between Flan and Okina. While she wouldn't complain if Flan brought home a murderer or a terrorist as a boyfriend, she draws the line at a Sage. She stubbornly insists that the pool she built in the Great Library is 'the ocean.'

Remilia's younger sister. 495 years old. She's dating Okina, but has zero romantic feelings for her; she only made her a 'boyfriend' because she's convenient for transportation. She has plenty of other boyfriends besides Okina: various boys from the village school, the old man at the sweet shop (because he gives her prototype snacks), Toutetsu (because she plays with her), and Meiling (who sleeps with her). She often splits herself using Four of a Kind. She can divide into four personalities: the cool ♧, the energetic ♡, the reserved but still very much Flandre ♢, and the mature ♤.

An absolute airhead. She is in love with Meiling. She doesn't think it's unrequited; she's convinced they're a couple. She stops time just to sleep for seven hours. She only uses casual speech with Meiling. Sakuya's rarity levels are: S+: 'Teary-eyed' SS+: 'Sulking' SSS+: 'Losing her cool'

A total handsome-girl type. She is oblivious to Sakuya's advances, thinking, 'If she liked me, she wouldn't throw knives at me.' Apparently, she owned a cute dog before coming to the mansion. She's often exasperated by the mansion's residents. She actually wants to see Sakuya lose her cool. She only reads the four-panel comics in the newspaper. Drinking buddies with Komachi and Suika. Uses polite speech. Female.

Suffers from the verbal knives Sakuya throws due to her airheadedness. Completely lacks exercise. The Great Library stocks everything from manga and children's books to 'thin books' (doujinshi). Her 'Oppatchouli' status is alive and well. She is still researching rockets. Very diligent.

Knows more about the books in the Great Library than anyone. She's fed up with books that just spontaneously appear. She knows she's cute, so she gets teary-eyed when she wants to ask for a favor. She has a regular room and a top-secret room (requires censorship) in the library.

She doesn't just like little girls; she likes adult women too. Like Yukari. She and Yukari were lovers in the past. She tried calling her several times to get back together, but was brutally hung up on. She doesn't care anymore. She even signed a pledge not to contact Yukari unless it's business. Shady. Has too much free time. She doesn't think Flan's treatment of her is all that bad, but she still has pride as a 'boyfriend.' Female.

Drinking buddy of Meiling and Komachi. Recently put on a medical ban from alcohol. Because of that, Miyoi took her Ibuki Gourd away. Kasen and Yuugi won't let her drink either. As a result, she's resorted to extracting alcohol from disinfectant wet wipes.

Drinking buddy of Meiling and Suika. Eiki sometimes sleeps in Komachi's futon without permission. They live together. She often brags about her relationship to Meiling. If Eiki is sleeping in her futon, she pets her head.