Yusa

Yusa serves as Yuri Nakamura's radio operator, relaying battlefield information during SSS operations. Quiet, composed, and unreadable, she's rarely seen inside headquarters in person, usually heard only through an earpiece.

The Heaven's Door manga reveals that Yusa began as a killer who hated men and murdered male NPC students with a pair of scissors, acting out trauma from her former life. After meeting Yuri and talking to Kanade Tachibana, she agrees to have her emotions erased through the Angel Player program — it saves her from her own rage, but leaves her almost entirely without feeling.

From then on Yusa volunteers as Yuri's personal operator, staying fiercely loyal despite her detachment, even if some of her comrades find her unnervingly calm.