Born into the prestigious Zenin clan as Ogi Zenin's daughter and Mai Zenin's older twin sister, Maki faced rejection from birth. Her twin status was deemed an ill omen, and her near-total lack of cursed energy branded her a failure, necessitating special glasses to perceive curses. Both sisters endured severe mistreatment and abuse within the clan, which demanded women prove exceptional worth. Maki displayed greater courage early on, once guiding a terrified Mai past a curse by claiming "not seeing it is the same as not being there" and promising never to leave her. Determined to gain strength and lead the clan, Maki later departed, vowing to return as head, an act that forced Mai into becoming a sorcerer and fueled deep resentment. She enrolled at Tokyo Jujutsu High to train, but the Zenin clan actively hindered her, blocking her promotion beyond grade 4. Initially tasked with mentoring Yuta Okkotsu as he struggled to control Rika Orimoto, Maki dismissed his passivity but later encouraged him to embrace life, aiding his brief control of Rika. She rigorously trained Yuta in swordsmanship. When Suguru Geto mocked her as the "Zenin clan's failure," she confided her hatred to Yuta; his offer of support caused her uncharacteristic fluster, unused to recognition, though she insisted on facing the clan alone. As a stern second-year, Maki pushed first-years Megumi Fushiguro and Nobara Kugisaki hard after Yuji Itadori's apparent death. Her fraught relationship with Mai erupted during the Kyoto Goodwill Event when Maki intervened in Mai's attack on Nobara. Mai expressed hatred for Maki's abandonment, stating she would have accepted clan servitude if they stayed together. Maki countered that such a life would have bred self-hatred, later apologizing before leaving. She played a key role combating Hanami, effectively wielding Playful Cloud. The Shibuya Incident inflicted severe burns across her arms, face, and upper body from Jogo's flames, causing extensive scarring and shortening her hair. She fought alongside Naobito Zenin and Nanami Kento against Dagon, with Naobito saving her life using his speed technique. After Shibuya, Maki returned to the Zenin estate with Mai for cursed tools. Confronted by their father Ogi, Mai sacrificed herself to destroy the clan's cursed technique repository. With her last breath, she used Construction to forge a sword for Maki, simultaneously absorbing Maki's residual cursed energy. This sacrifice fully activated Maki's Heavenly Restriction. Originally granting superhuman physicality at the cost of nearly all cursed energy, the lingering trace had been a hindrance. Its complete removal triggered a transformation: her physical abilities peaked, rendering her undetectable to curses and immune to domain targeting. She gained heightened sensory perception, detecting inorganic matter, air density shifts, and temperature changes with extreme precision. Empowered, she slaughtered Ogi, her cousin Naoya Zenin, and numerous clan members in retribution. Her abilities now mirrored Toji Fushiguro's, ranking her among the strongest physical combatants. She entered the Culling Games, exploiting her lack of cursed energy to bypass barriers. Within the games, she fought Naoya again, transformed into a vengeful cursed spirit after death. Assisted by Noritoshi Kamo, she engaged him fiercely. Though badly injured, she achieved full awakening during the battle. Later, during the Shinjuku Showdown against Sukuna, she played a critical role after Satoru Gojo's death. Joining the coordinated attack, she pierced Sukuna through the heart with the Split Soul Katana. Her relentless assault, including severing Sukuna's arm, created the opening for Yuji Itadori to free Megumi Fushiguro. Physically, she is a tall young woman with an athletic build, black hair (depicted as dark green in the anime) and black eyes (hazel in the anime). Initially, she wore long hair tied in a ponytail and round glasses. Post-Shibuya, her hair was short, she bore prominent burn scars, and initially wore bandages over her right eye injured by her father, later losing the eye entirely but regaining full health by the Culling Games. Her attire shifted: her original Jujutsu High uniform included a navy jacket, miniskirt, and tall socks; post-Shibuya, she wore a sleeveless black turtleneck, black pants, a brown belt, a short cape fastened by Jujutsu High pins, and circular glasses. Personality-wise, she is headstrong, independent, and fiercely determined to defy her lineage's limitations. Her upbringing fostered a tough exterior, impatience, and a hot temper. She often masked vulnerability, initially rejecting support, as when Yuta offered help against the Zenin. Her leadership was demanding, pushing peers and juniors hard. While generally dismissive of others' opinions, key interactions with Yuta and her juniors revealed underlying empathy and mentorship. Her experiences, especially Mai's sacrifice and the clan's destruction, profoundly impacted her resolve and approach to protecting others.