Shiina, given name unknown, otherwise referred to by his nickname Shii (しー), is an adult friend of Shuichi and Yoshino. The boyfriend of Hiroyuki Yoshida, he is portrayed as a carefree and understanding person who first took interest in Hiroyuki in high school where they were teased and bullied for being a male to female transgender teenager. He was Yuki's classmate in elementary school, but the two never interacted much until they entered the same high school. After graduation, Shiina learns that Yuki has transitioned to living as a female, prompting him to find her at the bar she owned . Unlike Yuki, Shiina had many friends in school. He generally just watches over Shuichi and Yoshino, along with Yuki, but he sometimes does bold and unexpected things.
Shii's Story (Anime)
When Shiina was very young, his two older sisters would dress him as a girl, outfitting him with pretty dresses and such. Shiina always knew that he was a male, but went along with the cross dressing to please his sisters. Gradually, the two sisters lost interest and drifted away from Shiina. Not many details are given about him, save that he is very caring towards Yuki and has been with her since the beginning of her transition to her correct gender of female. Shiina has always been encouraging, even when the chips were down. It is stated that he was the only one who accepted Yuki for who they were, even before they underwent the transition from male to female.