Blond hair tied in a messy ponytail, a mole below her left eye, wearing her school's uniform, with stockings with side patterns and high cut sneakers.
Nise was bullied and neglected by classmates and family alike. Thus, she learned to not trust anyone. This behaviour reached extreme heights when she reached this world, turning her into a seemingly cold-blooded killer, that is, until she met Yuri Honjo.
She is an experienced knife wielder, as seen by her body count of littered bodies. This ability heightened when she acquired the traits of an "angel", wearing the defective smiling mask, thus having the capability to perform fights in a way a normal human cannot do. Later on, in order to fight against the great angel, she used defragmentation to erase the mask's program and greatly increase her capability.
Nise considers Yuri a close friend, to the point she is willing to kill everyone who puts Yuri in danger, even considering to wear the "defective" smiling mask for the sake of saving her.
Entrusting the duty of protecting Yuri, she has somewhat possessed the certain protectiveness over her friend and always seen doing anything for her. There are signs that Nise has developed feelings for her.