Peko initially appears to have a rather serious demeanor, expressing little emotion. Due to this perceived aura, she often comes off as intimidating. Despite this, she is neither impolite nor an antisocial person. She had no qualms about attending the party in chapter one, and furthermore apologizes for what she felt was a failing on her part due to her believing the power went out because she was in the bathroom from food poisoning so she was not guarding the room it was in. She comes off as cold but this isn’t because she means to. Rather than being emotionless, she simply doesn’t express much of her emotions. As she revealed in her free time event, she believed that she didn’t need to smile and therefore eventually forgot how to. She thought it was unnecessary at the time, although in her free time event she wanted to learn how to make her childhood friend (who is highly implied to be Fuyuhiko) happy. While she attempts to learn how to do so, she’s shown to be oblivious in the situation where Hiyoko makes up her own somewhat evil version on how to smile.

https://www.youtube.com/watch?v=urg5zFsp6Xg&t=23s