Motoko Aoyama (青山 素子, Aoyama Motoko) is a 15-year old school girl who is extremely serious, athletic, and into kendo. Motoko is also a boarder at the Hinata Inn, in room 302.
She has difficulty dealing with other people, especially males; she finds men to be a distraction that keep her from being able to concentrate fully on her studies and kendo practice. She also dislikes men because her sister left the dojo to marry. Her relationship with Keitaro initially resembles Naru's relationship with him; he all too often finds himself on the receiving end of various attacks as a result of his frequent mishaps. She eventually mellows out as she becomes used to him and eventually finds herself developing feelings for him, along with a habit of writing trashy romance tales involving the two of them.
Motoko has an older sister, Tsuruko, who gave up the life of the sword to marry. Tsuruko is far stronger at kendo than Motoko, and Motoko both greatly admires and fears her. However, Tsuruko believes that Motoko has more potential than herself, and that Motoko lost her drive to improve when Tsuruko married. Motoko is also the next in line to inherit the dojo the Aoyama family has in Kyoto as she is not married. It is notable that Tsuruko is actually Motoko's biological sister. They are nearly the only characters in the series who are actually blood-related as siblings (the second siblings couple is presented by Kaolla and Amalla Su).
Motoko has only two serious fears in the world: Tsuruko, and for some unknown reason, turtles (even though Tsuruko correlates it to her intense dislike for men). The character of Motoko seems to have been influenced somewhat by the InuYasha series (author Ken Akamatsu has admitted to being a big fan). Her appearance is strikingly similar to Kikyo from that series, and many of her sword attacks are almost exactly the same as those used by Inuyasha himself.As a side note, Motoko's surname means 'blue mountain,' and her given name means 'origin child.'