Nightin is an elderly woman with light purple hair intricately coiled into a bun secured by crimson tassels, her eyes framed by glasses etched with swirling patterns and accentuated by sharp pink eyeliner. She dons a lab coat over a vibrant pink dress trimmed in emerald green, completing her ensemble with sleek pink heels. Consuming a bitter herbal elixir triggers a transformation, temporarily restoring her to a taller, youthful form—wrinkles vanish, yet her sharp features remain unchanged.

A prideful tactician, Nightin savors her unmatched medical and combat prowess, fiercely confident in her ability to challenge Boa Hancock. She devises cunning strategies, like swallowing acrid herbal tonics to resist hypnotic attacks, though overwhelming beauty fractures her defenses. Her demeanor blends playful mockery with ruthless efficiency, often addressing Marines as “sweeties” before launching calculated assaults.

Within the World Pirates, Nightin merges herbalism with combat through her signature Kanpo Kenpo, lacing strikes with debilitating toxins and strength-enhancing concoctions. A custom youth-restoring powder amplifies her agility and power during battles, though its effects wane over time, leaving her vulnerable in protracted fights.

Her history is anchored to the World Pirates’ clashes against the Marines, including the betrayal of captain Byrnndi World by crewmates swayed by the World Government. Forced to flee during the ambush, she later reunited with World after his Impel Down escape. During the 3D2Y incident, she confronted Boa Hancock aboard the crew’s submarine base, deploying rejuvenation and herbal defenses to briefly counter petrification. When her resistance faded, she fell to Hancock’s power, left petrified as Marine forces obliterated the World Pirates’ ship—her final fate lingering in uncertainty.