Kohiruimaki Yumi

A Caster who's a lecturer at the Academy.
She's like a reliable older sister, and is just as kind as she is strict.
Blessed with incredible magic talent, she graduated early from the Academy and now works there as a lecturer, while also lending her skills to BURST (the Bureau of Unregistered magic Regulation and Suppressive Tactics) in times of emergency.
Since she's close in age to the students of the Academy, many of them come to her for advice on various topics.