As of yet, Hibari is the only 10th generation Vongola guardian whose family is not revealed. It can be assumed at some point, that Hibari entered Namimori Junior High and became leader of the Discipline Committee. In the drama CD, "One Day Observation Report of Hibari Kyoya," Sasagawa Ryohei admits that Hibari had been Chairman of the Discipline Committee since he (Ryohei) first entered the school, implying that he either became the Chairman as soon as he entered Namimori Middle or that he is actually older (most assume it to be the latter). In chapter 45, Tsuna asks if Hibari is supossed to be graduated. Hibari replies that he can always picks whatever year he feels like, confusing Tsuna further. It is also believed that Hibari has not lost a single battle prior to meeting Mukuro for the first time.