Саґамі Рей

Rei is Sana's manager. After being dumped by his girlfriend, dropping out of college, and his parents' death, he hits bottom and becomes a homeless person. While begging on the streets, Sana finds him and brings him home much like she does with stray dogs (in the manga, they own three). Misako decided to keep him around the house, and he has lived there ever since, working as Sana's manager. Sana declares him as her "pimp" after reading a book which included the word, although she does not understand what it really means. In addition, Sana thinks of Rei as her boyfriend. Later, Akito tells Sana that Rei is playing with her, and sees her simply as a little girl wanting to play.

Misako also tells Sana that Rei cannot be her boyfriend. This leaves Sana devastated. But after she gets over her heartbreak, Rei remains her manager and her friend. (Source: Wikipedia)