The Ultimate Child Caregiver. She was raised in an orphanage and often had to take care of the children younger than her there; despite this, she does not like children. A mostly coolheaded girl. Although she was initially shown as a primary character along with Momota Kaito and K1-b0 in early promotional materials, neither of the three were the true protagonist.
At the end of Chapter 2, it is revealed that she is actually the Ultimate Assassin, using the title of Ultimate Child Caregiver as a cover to hide this.