Kirie is described as having an extremely menacing aura, which leads her to having few friends. It's also implied that she is actually quite shy to the point that she can only talk to small children, as seen with Umaru's indoor mode, which has the appearance of a child. She calls Umaru's indoor mode (Komaru) "Master/Mistress" and is in service to her.

She appears to be quite affectionate and loving toward Umaru and 'Komaru', however, she is often violent towards her brother Takeshi Motoba, to the point where she beats him up for eating her cookies. Her special skill is "concealing her presence," and it became a running gag in the series that she's invisible.