Rikuhachima Aru, the self-proclaimed "Boss" and president of Club Problem Solver 68 at Gehenna Academy, portrays a cool, beauteous, and villainous facade. Despite her mischievous and conceited exterior, she often breaks character, revealing a meticulous and caring nature when teased or pressured. Aru is a second-year student with a knack for accepting various quests, legal or not, wielding a Sniper Rifle as she aspires to make Problem Solver 68 a reputable criminal organization.