Nepgear is the CPU Candidate of Planeptune and younger sister of Neptune (Purple Heart), embodying a fictional Sega handheld console called the N-Gear—a reference to the Sega Game Gear—with data processing and organizational functionalities. She possesses long lilac-purple hair secured by a D-pad-shaped hair clip, purple eyes, and typically wears a white sailor-style uniform featuring purple accents, a yellow ribbon with an "N" emblem, and pink-and-white striped thigh-high socks. Upon transforming into her HDD form, Purple Sister, her hair lengthens with a pink hue, her eyes become bright blue, and she dons a white or black bodysuit with lilac or purple details, wielding a gunblade in place of her human form's beam sword. Unlike other CPUs, her personality remains consistent between forms—slightly more confident as Purple Sister but fundamentally gentle and merciful. Personality-wise, she contrasts sharply with Neptune: shy, diligent, and deeply responsible, she frequently over-apologizes and battles self-doubt, particularly after trauma like her three-year imprisonment alongside CPUs at the Gamindustri Graveyard by CFW Magic. She shares a close bond with Neptune, affectionately calling her "sister," and is protective of friends like Uni, Rom, and Ram. A technological genius especially with robots, she repairs giant mechs and exhibits erratic enthusiasm when handling machinery, a quirk Neptune questions. Her story begins in *Hyperdimension Neptunia mk2*, rescued by IF and Compa after years of captivity. Initially unable to transform due to trauma, she regains her HDD ability when IF sacrifices herself against Underling (Linda), transferring power through a kiss. As protagonist, she recruits CPU Candidates Uni, Rom, and Ram to rescue captured CPUs, facing antagonists like CFW Judge and Arfoire. Key moments include awakening the "Lilac mk2" processor unit to defeat CFW Judge and experiencing endings like the darker "Conquest" path, where she shoulders grim responsibilities alone. In *Hyperdimension Neptunia Victory*, she accidentally travels to the Ultradimension and briefly grapples with depression when Neptune bonds with Plutia, feeling replaced—until Neptune reassures her of their sisterly bond. Vert gifts her a CPU Memory to reactivate her HDD form, sparking conflict when Vert claims her as a sister, leading to battles and unsettling encounters with Plutia’s alter ego, Iris Heart. Across spin-offs and media, she supports Neptune’s idol endeavors in *Producing Perfection*, battles zombies in *MegaTagmension Blanc*, serves as a mage-class beta tester in *Cyberdimension Neptunia: 4 Goddesses Online*, and investigates mysteries in the *Megami Tsuushin* light novels. She also features in non-*Neptunia* collaborations via costume sets in *Mugen Souls* and as a playable unit in *Sangoku Taisen Smash*. Her abilities include combat techniques like "Mirage Dance" (sword slashes) and "Slash Wave/M.P.B.L." (energy blasts), alongside summoning mechs such as "Nepgeardam." She utilizes support magic for healing and stat boosts, reflecting her "red mage" versatility. Trivia notes her popularity—ranking third in mk2 polls—and her gunblade’s design reference to the *Virtual-On* series’ Temjin.