She's Hazuki Ren's mom. Back in the day, she was an idol herself—part of some school idol group whose name has been lost to time. She actually attended Jinguu Music Academy before it shut down, but she didn't just accept that the school was gone. She went on to reopen it and transform it into what's now known as Yuigaoka Girls' High School.
Content compiled by AnimeList.moe from publicly available sources.
