Hiyoko's cute appearance, voice, and (initially) her way of talking give off the impression she is innocent and childlike. However, in her introduction alone, it is revealed that she is very direct and cruel with a side of malice. While not violent towards people (presumably due to her diminutive stature), Hiyoko often shows similar mean behavior towards them. She constantly judges others and patronizes them with rude insults, and sometimes with swearing. She bullies Kazuichi & Mikan the most.