Motoko Aoyama is a 15-year-old high school girl who is very formal and into kendo, to the point that her room resembles that of a samurai's (complete with a suit of armor). She claims lineage to a school of demonslaying swordsmen and also displays a prodigious competence with her katana. She can often wreak great damage to boulders or other objects using nothing more than her wooden practice sword. Motoko is very terrified of her sister, Tsuruko, whose skill far exceeds her own, and has a phobia of turtles that is left unexplained for the majority of the series. She disapproves of Keitaro early on, on the basis of him being a letch and a weakling, but later develops a grudging respect and eventually a hidden affection for him (much to her chagrin). She is at first uncomfortable with her femininity, partially because her sister left her sword for a husband, partially because of her height: she is the tallest person in the house, 3 cm taller than Keitaro(171cm). She later becomes more open due to Keitaro's influence. Whatever her feelings for Keitaro happen to be at a given time, she still frequently threatens or attacks him with her sword.