She entered Suiran Academy in the Primary Section. Although her family is decently well off, they are not wealthy enough to enter the Pivoine. She does not like attention.
Ririna and Tsugumi are classmates and friends. Ririna first approached Tsugumi, and although Tsugumi doesn't really like the attention Ririna is giving her, she still ends up getting caught in the whims of Ririna.
She now considers Ririna her friend. She was ready to ask Reika for forgiveness in behalf of Ririna when Ririna messed up stalking Kaburagi Masaya. She also know that Ririna actually looks up to Reika, despite what Ririna says.
Reika describes her as “oddly well-informed” and has quite the gossip. [c72] Tsugumi tells Reika all sorts of things, ranging from funny stories to useful intelligence. [c72] Tsugumi is Reika’s informant, and helps her in various stalking activities, such as the investigation on the girls that surround Akizawa Takumi: his club kouhai and the Track Club Manager [c68]. She was also responsible for supplying the information regarding the Soccer, Basketball and Baseball Club presidents that Reika used during the Club Presidents’ Meeting in Reika’s 2nd year of high school.