Kotegawa Yui

An uptight, high-strung girl who is in Rito's class during the second year, Yui has little to no tolerance for anything she does not consider to be "acceptable behavior", ironically despite this seems to secretly desire for Rito to do them to her (where in the OVA 5 she states "you can only do naughty things to me"). Her haughty opinions, quick temper, and habit of speaking her mind often results in her vocally reprimanding classmates. Yui quickly grows annoyed and disgusted by eccentricities and bizarre actions, particularly with regards to Rito and Lala.

Unfortunately, almost every encounter with Rito usually ends up with her embarrassed, naked or groped, and although though her nature prevents her from easing her behavior, she does slowly warm up to his usual antics. After Rito saves Yui from a group of delinquents, she develops feelings for Rito, although her inexperience with boys leaves her unable to understand her feelings and continually denies her feelings to herself. And when Rito usually asks what's wrong, she says the exact opposite of what she wants to say and then hurts him in some way (a typical Tsundere).

A common gag is that newer characters cannot remember Kotegawa's family name, presumably due to the fact she is generally an unwilling participant in Lala's frequent schemes. Also she really likes cats – owning cat based books, having a stuffed cat, decorating her room with cat shaped things, shaping her chocolate into a cat's face, and even having a cat-themed floaty, something Rito seems to find cute about her. According to Mio Sawada, her measurements are B88, W59, H87

Relationships with Other Characters
Rito Yuuki Throughout the series, Yui's love intrest has developed. Originally thinking he was just a "Shameless," boy, she realized how she was wrong after seeing Rito's kindness around town. Later at a group picnic, Yui told Rito that she state that "I won't let you do shameless things with anyone else but me!!" However this was because she was under the influence of pollen that caused all the girl's to fall in love with Rito. Yui also made chocolate for Valentines Day, even though she claimed to him it was just "Giri (Obligatory) Chocolate," but really it was only for him.

In To Love Ru: Darkness, While Momo is trying to further her Harem Plan, in which Rito will marry all of the women who love him, she influences the weather when Rito and Yui are walking home so that they go to Rito's house for shelter. While there Yui starts to confess to Rito, stating how it is normal for boys to do "Shameless things," and nearly comes close to kissing him, but she backed out. Yui announced her love for Rito, albeit only to herself, she finally came to terms with it.

Lala Satalin Deviluke While Yui is generally very uptight, and in some senses Lala's complete opposite, she still is her friend. However Lala's outgoingness with Rito often leads to Yui considering it as "Shameless," however that is the norm with her.