Isuzu, who is more commonly referred to as "Rin" because it's an alternative way of reading the second kanji of her name, is the horse of the 12 cursed zodiacs. She is stubborn, independent, and sharp-tongued, but she cares for others deeply. Such traits are associated with people who are born under the Year of the Horse.
She and Hatsuharu have a close relationship with one another, which is unapproved by Akito and forcibly put to an end. Rin loves Hatsuharu very much and decides to find a way for him to break away from the curse, even if it meant receiving more punishment from Akito.
Rin only appeared in the manga, so people might not know her. But this is really a nice cosplay of the two zodiacs! It's just disheartening how much abuse Rin received at such a young age. Nice cosplaying though!