One of the three presidents of the Tea Party, Trinity's student council, and the leader of the Filius Faction. Nagisa is also Mika's childhood friend. In contrast to Mika, Nagisa thinks first before acting, sometimes thinking a bit too much to the point where she causes problems for others who are uninvolved or are supposed to be considered innocent. Compared to the other Tea Party members, Nagisa's political prowess seems to be the highest.