Ai Kitora/Plot

Background
When she was in B-Class, she rose through the ranks as a Gunner, but started using Scorpion because bullets were too Trion-consuming, especially with her low Trion. When she was still in high school, she became an A-Class member of Border. She was trained by Karasuma in the past, just like Osamu is now.

Introduction Arc
She first appears with Arashiyama, responding to an attack on the school. Upon learning that Mikumo had breached the rules, she scolded Arashiyama for praising Mikumo and berated Mikumo in turn. Kuga contradicted her by questioning her line of reasoning, saying that Triggers were originally Neighbour technology. She became embarassed, and this deepened as Kuga continued on with how she merely being spiteful.

Kitora, later on, was sent to 'escort' Mikumo to Border HQ, stating that she was there merely to ensure Mikumo doesn't run.