Like Dabi and Spinner, she idolizes Stain and his ways of life and decided to join the League, which was believed to harbor the Hero Killer's cause. However, unlike the other two, she is only interested in Stain's ideals. She serves as the archenemy of Ochaco Uraraka.
 
Himiko is very gleeful, jubilant and charismatic, but also very psychotic when it comes to people she thinks are attractive. She is seen with a smile most of the time and has an extremely effervescent and joyous expression. She has an extremely enthusiastic and carefree nature to her, as seen by how she does not mind calling someone she fights a friend like Ochaco Uraraka and Tsuyu Asui.