Yukako Yamagishi

Yukako Yamagishi is a fictional character from Part IV: Diamond is Unbreakable.

Personality
Yukako is a particularly determined person, especially when considering her love interest Koichi Hirose. This determination translates into various actions, from aggressively attacking potential rivals in love to forcibly correcting Koichi to make him a better person, and even requesting the services of Aya Tsuji to make her more attractive to him.

Synopsis
At first, Yukako was very aggressive in her affections towards him, jealously attacking what she believed were potential rivals in love and even going so far as to kidnap him and threaten his life should he not return her feelings and not appreciate her efforts to "change him into a better person" – she had picked up false rumors that were spread by Josuke and Okuyasu in order to help Koichi turn her away from him; unfortunately for them, their measures had the opposite effect.

Later in the story Yukako, still lovestruck, seemed to have learned from her mistake in trying to force Koichi. Unhappy about her unrequited love she made use of the services offered by Aya Tsuji's beauty enhancing Cinderella stand, which rendered her into a bewitchingly attractive woman in the eyes of Koichi - for a price and a certain time limit, during which she was to use a special lipstick in order to uphold the "magic" i.e. the stand's power. The stand allowed her to grow closer to Koichi, who, after some trials and tribulations, warmed up to her and willingly became her boyfriend.

However, when she forgets to apply the magic lipstick, she becomes furious and flies into a rage at Aya, who grants her a chance for her to return to her original appearance should she be able to pick her original eyes. Yukako has trouble picking the right one until Koichi arrives to her aid and decides that he will pick for her, but requesting Aya that she take away his eyes should he make a mistake. Aya, unwilling to take the role of an antagonist, decided to give Yukako her original appearance back.

Trivia

 * Okuyasu Nijimura seems to be a secret admirer of her.
 * Her house is located at the edge of Morioh-cho, right by the cliffs of the sea.