Megumi Fushiguro is a first-year student at Tokyo Jujutsu High and a Grade 2 jujutsu sorcerer. He is the son of Toji Fushiguro, the infamous Sorcerer Killer who abandoned the Zenin clan, and the stepbrother of Tsumiki Fushiguro. Because he inherited the Zenin clan's prized Ten Shadows Technique despite his father lacking cursed energy, Megumi became a target for the clan, but Satoru Gojo discovered him during his early school years and took him under his protection, enrolling him at Jujutsu High. Megumi's early life was shaped by tragedy and responsibility. After his father's death, Tsumiki became the cornerstone of his moral compass, and her kindness instilled in him a deep belief in protecting good people who are unfairly affected by circumstances beyond their control. This philosophy drives his main motivation: to save Tsumiki and to defend ordinary people from curses. He often views his role pragmatically, stating that he is a jujutsu sorcerer, not a hero, and he accepts that saving everyone is impossible.

Megumi's personality is reserved, stoic, and deeply analytical. He rarely displays strong emotions openly and tends to internalize stress, which can manifest as irritability toward the playful antics of Gojo or Yuji. Beneath his aloof exterior lies a calculating mind and a strong sense of justice. He is not motivated by clan loyalty or material wealth, instead valuing human welfare above all. This sometimes leads him to undervalue his own life, willingly sacrificing himself if it means protecting those he deems worthy. His self-destructive tendency becomes a recurring theme throughout the story, especially as he faces increasingly dire situations.

In the narrative, Megumi serves as the deuteragonist alongside Yuji Itadori. He first appears when Gojo sends him to retrieve one of Ryomen Sukuna's fingers, leading to his encounter with Yuji. After Yuji ingests the finger, they become partners and classmates. Megumi's key relationships include Yuji, with whom he shares a strong bond despite their opposing philosophies—Yuji believes everyone can be saved, while Megumi is more selective. Their dynamic explores the moral core of the series. Gojo acts as both mentor and protector, pushing Megumi to realize his own potential. Nobara Kugisaki is another classmate, forming a reluctant but effective trio. Tsumiki remains his primary emotional anchor, and her eventual cursing during the Culling Game drives him to desperate measures, including the revelation that she was possessed by Yorozu, which temporarily shatters his will. The relationship with his father Toji is also significant; Toji is resurrected temporarily during the Shibuya Incident and, upon recognizing Megumi, chooses to destroy himself.

Megumi's development progresses from a cautious, self-doubting sorcerer to a more confident and powerful fighter. During the Kyoto Goodwill Event, he demonstrates tactical brilliance against special-grade curses. At Yasohachi Bridge, he unlocks his incomplete Domain Expansion, Chimera Shadow Garden, for the first time while fighting a Finger Bearer. The Shibuya Incident tests his resolve severely, pitting him against powerful cursed spirits and forcing him to confront his father's legacy. In the Culling Game, his desperation to save Tsumiki leads to increasingly reckless actions, and after Sukuna takes over his body, Megumi suffers permanent physical and emotional scars. His eventual separation from Sukuna leaves him with three facial scars and a deepened understanding of his own worth.

Megumi's primary ability is the inherited Ten Shadows Technique, which allows him to summon shikigami from shadows using hand signs that resemble shadow puppets. His shikigami include the Divine Dogs (tracking and combat), Nue (flying and electrical attacks), the Toad (restraint and rescue), the Great Serpent (restraint, later destroyed by Sukuna), Max Elephant (water blasts and crushing weight), Rabbit Escape (dozens of small rabbit decoys), Piercing Ox (charging impact), and Round Deer (healing via reverse cursed technique). Mahoraga, the Eight-Handled Sword Divergent Sila Divine General, is the most powerful but also a suicidal last resort that can adapt to any phenomenon. Megumi can also combine shadows for hybrid shikigami and store objects or himself within shadows for ambushes. His Domain Expansion, Chimera Shadow Garden, turns the battlefield into liquid shadow, enhancing his shikigami and allowing multiple summons simultaneously. Though incomplete, it can negate enemies' sure-hit effects when used inside another domain. Megumi is also proficient in hand-to-hand combat and skilled with cursed tools, often coordinating attacks with his summons. His strategic thinking and large cursed energy reserves make him a formidable sorcerer recognized by both Gojo and Sukuna as having the potential to surpass even special-grade opponents.