Shima Kurosawa is a rival to Densuke for Chiharu's affections. He is the antagonist in the OAV.
Shima is almost the exact opposite of Densuke. Tall, handsome, smart, as well as skilled with machines, cooking, etc. He is also a lady's man and is able to effortlessly have almost every girl in school fall for him. However he does have one glaring flaw....
After returning from an exchange program in America, Shima proceeds to effortlessly "woo" nearly every girl in the entire school, even seeming to make Chiharu blush near him. When he tried to make his move on Chiharu, Kirika suggested a contest between him and Densuke to see who would get the girl.
Shima completely dominated Densuke in every event. Racking up perfect 10s in all events (except for Mifune who gave him 9.) However in the last event when Densuke actually managed to beat him it was revealed Chiharu was only blushing when sick and had been avoiding Densuke because she didn't want to give him her sickness.
At the revelation that Chiharu liked Densuke and not him, Shima's true attitude is revealed. He threw a childish tantrum, crying and complaining why no girl he ever liked liked him back. Revealing he also wanted Kirika, she said she only liked Densuke. The girls who once liked him found this a great turn off.
Anime
In the anime, he is trying to seduce Chiharu much to Densuke's frustration. He has a harem of identical bikini clad maids to do his bidding. He has also placed a spy camera in the ceiling fan of the Eiken club to watch club meetings. During the sports festival, he partnered up with Chiharu and made several advances toward her during the contests. In the final contest (pudding slide) he once again shows his 'crybaby' nature when Chiharu chooses Densuke over his. He reveals he put a spy camera in the club then falls off the slide, revealing that his hair is also a wig and that he is bald.