居待月夜

A girl who got assigned to the 8th Training School at roughly the same time Takaya joined.
Before then, she belonged to the 4th Unit lead by one of the Hakkenshi, but after his disappearance endorsed by the Gotou Faction, along with repeated battles, the 4th Unit has been completely destroyed. She is the lone survivor from that unit, being a lower class non-combatant then.
Because the 4th Unit is one of the strongest groups combat-wise under Son's leadership, her ideology is also greatly affected by them, which leads her to being a greatly athletic-minded combatant.
In reality, she belonged to a 3rd party unit from the Mainland, with her sisters as members, that killed off the 4th Unit. She joined Hachiren as a spy, with a mission given by her sisters to gather information.