Origin
Japan
Shiina is a "self-proclaimed female ninja" who fights with traditional Japanese weapons such as dual-wielding kodachi and shuriken. Shiina also wears the special uniform of the SSS, along with a long black scarf covering the bottom part of her face and her neck. Her skirt is slightly different from the usual, as it has two short slits which is probably to aid her in movement. She usually puts up a tough and quiet front, but she is extremely fond of cute things, especially stuffed animals. She is able to sense when danger is coming. She is very strict in her training and would continue with her training even when she is needed to do something else. Shiina's training mostly consist of balancing objects such as broomsticks, scissors and mops on her fingertip, sometimes balancing one on each of her fingers simultaneously while doing something else. She also usually says the phrase "how shallow-minded" when she remarks on her colleagues' actions.

Angel Beats!
Otonashi awakens only to learn he is dead. A rifle-toting girl named Yuri explains that they are in the afterlife, and Otonashi realizes the only thing he can remember about himself is his name. Yuri tells him that she leads the Shinda Sekai Sensen (Afterlife Battlefront) and wages war against a girl named Tenshi. Unable to believe Yuri's claims that Tenshi is evil, Otonashi attempts to speak with her, but the encounter doesn't go as he intended. Otonashi decides to join the SSS and battle Tenshi, but he finds himself oddly drawn to her. While trying to regain his memories and understand Tenshi, he gradually unravels the mysteries of the afterlife.