Summer, Lemon, and Overlay - Ch. 4 - Pride

[Suzushiiro]

Considering how she acts here and the earlier scene where she really doesn't want Konno to know her real name I'm guessing Yunimaru comes from a pretty rich family- maybe not rich enough that a normal person would recognize her last name, but rich enough that someone from a similar background like Konno would know. Konno, whose whole deal seems to be that she grew up just doing what her parents told her to do and it made her so miserable she now wants to die, probably knew this from the start (possibly because they met before) and the whole reason why she reached out to Yunimaru in the first place was because she saw her as someone who came from a similar background but took a different path.