Sunako's rich aunt who expects Kyohei, Takenaga, Yuki, and Ranmaru to turn Sunako into a lady in exchange for free rent. She is always traveling and searching for a new boyfriend.
Mine is a complicated character who makes an appearence about once an episode; she usually shows up just to tell the boys their rent has been raised. She is insanely rich and has many villas throughout the world, along with her own elongated private jet, and squad of helicopters she uses to jump from to make a magnificent entrance followed by a sudden departure with a jet pack.
She is always seen with a handsome man on her arm and swoons over his kindness and compliments but her boy toys never stay long. She usually ends up breaking up with them after a couple days.
According to the anime, Mine's husband died shortly after Sunako's parents' death and she was left in care of the young Sunako was only beginning to grow attached to dark things. She was so heartbroken she couldn't cry and Sunako offered to shed her dear aunt's tears for her. Mine denied her and told her to wipe her tears because a lady doesn't cry. Sunako responded that a lady should be allowed to show her feelings, and her aunt only smiled sadly at her. From then on, Mine was furiously dating for someone to take the emptiness in her heart away, but no man was like her perfect husband. Later she gave up altogether in finding a replacement and simply enjoyed the pleasure of another person's company no matter how brief.
When Sunako was young, Mine understood her obsession for dark and scary things and always encouraged her to be herself; no matter how creepy. But seeing as she was now a teenager, Mine wanted her to become a lady while still being herself.