Neito Monoma, hero name Phantom Thief, trains as a Pro Hero student in U.A. High School's Class 1-B. His childhood dream faced resistance due to societal views on his Quirk, Copy, which duplicates others' abilities but depends entirely on external sources. Repeated assertions that Copy was unsuitable for hero work fostered deep insecurities about his individual worth, leading him to self-identify as a "side character" compared to those with inherently powerful "main character" Quirks. This perception fundamentally shaped his worldview and competitive drive. Physically, he has average height and build, slick blond hair parted to the right with bangs often covering his right eye. His periwinkle blue eyes, usually half-closed and slanting downwards, combined with a frequent smirk and head tilt, create a default contemptuous expression. His hero costume is a distinctive black double-breasted tuxedo with long tails, featuring two belts around the waist from which three clocks hang to track his Quirk's time limits. He wears an upturned shirt collar with a light and dark blue dotted tie and a blue handkerchief in the breast pocket, completed by simple white shoes. Post-graduation, his appearance matured: taller and leaner, hair styled into two slick fringes, adding clock earrings and light-colored gloves to his costume. His personality exhibits significant duality. Around Class 1-A, he displays overtly mocking, sarcastic, and provocative behavior, launching vocal tirades and deranged laughter to belittle their achievements while extolling Class 1-B's superiority. This stems from envy over Class 1-A's disproportionate public recognition after incidents like the U.S.J. attack and his own insecurities about his Quirk's perceived lack of inherent heroism. Outside these interactions, he demonstrates calmness, kindness, and high intelligence. He deeply cares for his Class 1-B peers, offering strategic guidance, comforting them after losses like Setsuna Tokage, reassuring Eri, and showing concern for their well-being. He functions as a co-leader alongside Itsuka Kendo, respected for his tactical mind despite classmates often downplaying praise to avoid inflating his ego. His speech is verbose and eloquent, especially when addressing Class 1-A. Underneath his competitive facade lies an inferiority complex; he deliberately provokes Class 1-A to motivate his own class and mask self-doubt, sometimes resorting to underhanded tactics like blaming Katsuki Bakugo for All Might's retirement to gain psychological battle advantages. His primary ability is the Quirk Copy, enabling him to duplicate and use another person's Quirk for ten minutes after skin contact. He can hold up to four Quirks simultaneously but activate only one at a time. Copied Quirks retain all advantages, disadvantages, and required conditions of the original, though he cannot utilize Quirks reliant on pre-accumulated resources like One For All or Rewind. Physical limitations also restrict his safe use of Quirks demanding specialized conditioning. The three clocks on his costume track time limits, a number he admits is partially a ruse to mislead opponents about his capacity. Beyond his Quirk, he possesses exceptional strategic intellect and analytical skills. He devised Class 1-B's plan to place mid-rank in the U.A. Sports Festival obstacle race to observe opponents while concealing their abilities. He recognized Ochaco Uraraka's hidden strategy against Bakugo when seasoned Pro Heroes missed it. His combat style emphasizes agility, precision, and clever Quirk application over direct melee prowess. He effectively employs copied Quirks, such as combining Katsuki Bakugo's Explosion and Eijiro Kirishima's Hardening during the cavalry battle to ambush opponents, or using Nirengeki Shoda's Twin Impact with delayed timing to hinder Izuku Midoriya during joint training. His character development culminates during the Final War. Tasked with a pivotal role due to enhanced Copy abilities – now holding multiple Quirks for extended durations – he overcame initial apprehension about his "side character" status. Copying Kurogiri's Warp Gate, he dispersed combatants across Japan to contain the conflict. Simultaneously copying Shota Aizawa's Erasure Quirk, he helped suppress Tomura Shigaraki's powers, manually maintaining eyelid moisture to counteract the Quirk's drawback. Witnessing Bakugo's severe injury elicited visible empathy. Post-war, his contributions were formally recognized: he graduated U.A., became the current No. 10 Pro Hero, and received a statue erected at U.A. High School. Elements of his eccentric personality persisted. Neito Monoma's journey reflects the struggle to define heroism beyond innate power, leveraging intellect, adaptability, and unwavering dedication to support others, ultimately transforming from a self-perceived supporting player into an essential hero.