Reika Shuu is a Chinese student at Seika School for Girls, hailing from a wealthy Hong Kong merchant family. Her background includes Triad training, granting exceptional martial arts expertise that positions her as the group's primary close-quarters combatant. She stands 1.55 meters tall, weighs 43 kilograms, and has brown hair with grey eyes.

Reika operates within a tight-knit team alongside Kimiko Ayanokouji, Miyuki Ayanokouji, Youko Ryuuzaki, and Nina Kirov. Together, they defend against assassination attempts orchestrated by mercenaries under Col. Kartz. Her combat skills are consistently deployed in these defensive engagements, focusing on group survival and neutralizing threats within the school setting.