Suzu Shutou, designated No. 7 in Class Black, possesses short cyan hair and striking golden eyes. Though her youthful appearance mirrors a teenager, she has endured over a century of life due to Highlander Syndrome, a condition halting her aging. This affliction fuels her determination to join an assassination mission, driven by the desperate hope of finding a cure.

Her methods blend cunning and spectacle, centering on games of strategy—playing cards and pool become lethal tools. She crafts structured challenges with clear rules, granting targets a genuine opportunity to outmaneuver her plans. This calculated approach underscores her preference for intellectual rivalry over brute force.

After failing her mission, Class Black expels her. In the aftermath, she visits the grave of a past lover, revealing layers of personal loss and enduring emotional bonds. Confrontations with key figures, including her intended target, reshape her resolve, steering her toward prioritizing her own survival and future despite her unchanging form.

Records note her birthday as July 14th, though the fragmented timeline of her prolonged existence omits early history. Details beyond her role in the assassination plot remain scarce, emphasizing her struggle against the existential confines of her syndrome.