Even when he was younger, Megumi was very stern, earnest, and thoughtful, to the point where Gojo questioned if he was a first-grader when they first met. He didn't care for his father and assumed he and Tsumiki were abandoned. Megumi understood his situation with the Zenin Clan and stood firm that he would only cooperate if Tsumiki were happy as well. Now that Megumi is 18, he is very outwardly stoic, aloof, and calculating individual. He usually has a neutral facial expression that he rarely changes, making it appear as if he takes every situation seriously. This contrasts heavily with Yuji, Nobara, and Gojo's outgoing and goofy personalities, which often annoy Megumi. He's easily irritated and Yuji has noted that Megumi seems like he's always slightly angry.Megumi is a relatively tall and slim young man with fair skin and green eyes (dark-blue eyes in the anime adaptation) that slant upwards to denote his harsher and colder personality. He has uniquely styled black hair with long spikes that jut out in every direction around his head, resembling a sea-urchin (according to Kinji Hakari). When first meeting Megumi, Gojo noted the resemblance to his father Toji, and Megumi himself has similar facial features and the same green eyes as his late father.