Tsubomi tends to act mature for her age, and is often capable of cowing senior students by pure force of personality. She also seems to have a crush on Hikari, although she calls it pure admiration. Also, she often lectures Hikari and Yaya when they do something wrong in regards to their school work and responsibilities. She is a member of the St. Spica Choir and it is believed that the reason she joined was because of Hikari, though Tsubomi denies this. There are some very faint indications that Tsubomi may be developing an interest in Yaya, later in the series.
Tsubomi sometimes gets embarrassed when around Hikari due to either what Hikari says or of what others say. She tends to get angry or flustered easily, giving her an outspoken and very expressive personality. In effect, she can be loud in her opinions of others.