Chihiro Sengoku (千石 千尋 Sengoku Chihiro) is the advisor of Sakura Dormitory and an art teacher of Suiko. Despite being a teacher, Chihiro is lazy and only cares about drinking alcohol and trying to date men. Despite being a teacher, she often gives Sorata Kanda improper advice. She is also Mashiro Shiina's cousin and is the one who arranges the transfer, but she forces Sorata to take care of Mashiro due to her laziness. She was a conscientious student of Suiko, and wanted to become a professional artist, but she changed and became an art teacher because of Kazuki Fujisawa wanting to be a game designer.
Chihiro is an attractive adult woman with reddish-brown hair and eyes and large breasts. She wears vests of either purple or pink, a skirt, and high heels.
Chihiro may be a teacher, but most of the time, she merely cares about beer and men. She justifies this by saying that the two are things that she loves to do, and other more important factors like taking care of the residents are things that would make her sad, if she would do it.
Despite her shirking off the responsibility as dorm teacher of Sakurasou, she loves the residents dearly, as evidenced by her act of defending the dormitory against its demolition.
Chihiro doesn't mind so much for modesty and decency, as proven by her racy outfits and alcoholism. In fact, she sometimes gets offended when certain people point out that she has a drinking problem.
Their relationship isn't often during the series, but she offers him advice from time to time on how to deal with his conflicts and especially with Mashiro.
Mashiro is Chihiro's cousin from England.
- "Respect? I left that in my old man's testicles." to Sorata when he asked if she didn't have any respect for her job
- "The problem is you're trying so hard" to Sorata
- "If you only accept things that meet your ideals precisely, you'll make yourself and everyone around you unhappy." to Sorata about his attitude towards Mashiro
- "What an idiot. You really are a kid. You see the world in black and white. But the world isn't that simple. Everything around you is somewhere in the middle. They're not black or white. They're grey. Understand?" to Sorata after his arguments with Mashiro