A third-year student at Trinity General School and one of the three student council presidents of the Tea Party. She is also the leader of the Filius faction, one of Trinity's three major branches. The Tea Party follows a rule where the supreme authority of "Host" is rotated; while it should currently be Seia's turn, Nagisa is serving in her stead due to certain circumstances and holds the authority of the student council president. However, when irritated by reports of repeated turmoil, she has been known to lash out with outbursts like, "I'll personally shove macarons down your throat until it splits!" Though she usually behaves with elegance, she has a tendency to lose control and let insults fly when her emotions run high. When Mika wouldn't stop talking, she once tried to shut her up by threatening, "I'll shove a roll cake in there!" and actually attempted to block her mouth with one.

One of the three student council presidents of Trinity General School. She is the head of the Paternus faction, one of the three major branches forming Trinity, and a member of the Tea Party student council. She has an innocent and cheerful personality, and is a self-proclaimed "selfish and moody" person. As she says herself, "I'm not exactly the smartest," she behaves based on extremely emotional and personal whims despite being a representative of the school. When a general examination was to be held at Trinity, Sensei expressed a hint of concern regarding her grades; however, according to Nagisa, Mika is a classic case of someone who is "naturally brilliant but doesn't put in the effort." Far from being unintelligent, she is actually quite the opposite, and it is noted that she will be fine for the exams.

A member of the Tea Party, the student council of Trinity General School. She is also the leader of the Sanctus faction, one of Trinity's three major branches. Among the three presidents, she was serving as the "Host" (the de facto head president) for the current term, but she is reportedly hospitalized due to her frail health. Consequently, Nagisa of the Filius faction is currently serving as Host in her place. She possesses a very powerful ability for foresight, making her a unique individual even among all the students of Kivotos. Because of this power, she was once referred to as the "Archangel of Prophecy" by Beatrice.