Kazuya Todoroki is the third child of Endeavour and Rei. She is the younger sister of Fuyumi and Touya, and the older sister of Natsuo and Shoto. Ever since she was little she had formed a strong bond with her brother Touya. But after his death she grew depressed, feeling neglected and angry towards her father. Pursuing her career, she secretly hoped for some miracle that would expose her and her siblings abused past to the world.