Shigure is laid-back and anything but solemn. He is a flirt, a tease, and often acts like a pervert. Akito once remarked, that, "I thought you'd sleep with any woman." He likes to tease Tohru about going on a date with her, and also says he likes high school girls. As a writer of both romance novels and academic books, Shigure loves to drive his editor, Mitchan, insane. His most famous and well-celebrated pen name is Kiritani Noa (western order, Noa Kiritani), which he usually uses for his romance novels, as 'Summer-Colored Sigh,' which he showed to Saki Hanajima, Arisa Uotani and Kyo Sohma. They give very different reactions, Hanajima asks if a sequel will be coming out, while Uotani says it is unacceptable to write that 'smut' and Kyo comments that it's sick. Tohru thinks it's amazing that she knows an author. Usually, he makes the editor suicidal by telling her that he didn't write anything yet, though he is finished already.
Occasionally, Shigure shows that he has another side to himself. He can be surprisingly mature, thoughtful, and gives rather sage and insightful advice to Tohru, Kyo, Yuki, and other characters, acting like an actual "adult". Only in the manga is it revealed that he is also quite cunning and somewhat dark-humoured. It could be said that in some ways Shigure is the one who is most affected by the curse, being in love with Akito and at the same time considered beneath her. It is also speculated and revealed in the manga that, although he does feel brotherly affection for her, Shigure is actually using Tohru Honda to break the Sohma curse. This is not true in the anime. Shigure is normally seen in a traditional kimono. Occasionally when he does business, he wears western style clothing (a suit). Naturally Shigure wears either a gray robe or a navy kimono. In the house, he normally walks around bare-footed while everyone else wears socks. He has his specific reasons for doing so, since it is his house.
Shigure's best friends are Hatori Sohma
and Ayame Sohma
, who are also his cousins and possessed by the spirits of the Chinese zodiac. This trio has been friends since their childhood and are nicknamed the Mabudachi Trio. They were extremely popular in high school with many people admiring as well as being afraid of them. Ayame and Shigure sometimes pretend that they are lovers and regularly get into trouble, in which Hatori always soughts it out. Shigure can be quite manipulative for his intentions with Tohru Honda
thus Hatori once saying that he will "one day push too hard". The three of them are one of the only people who know that Akito is a girl, having been born before her. Shigure regularly looked after and protected Akito when the were younger.
However more than once, he provokes Akito Sohma with apparently undiplomatic responses that create other confrontations, such as Akito's visit to the summer beach house in volumes 10 and 11. Shigure eventually admits to Kureno Sohma that he hopes the disruption Tohru has caused will further weaken the weakening zodiac curse, and gives Tohru hints to figure out how to break it herself. Shigure's deepest feelings are for Akito, and he once had sex with Akito's mother, Ren, because he was upset that, although Akito secretly felt the same of Shigure, she was sleeping with Kureno. In the end, it is implied that Shigure's machinations have all been aimed at freeing Akito from the curse and the need to live as a man, so that he can have her to himself. He gives Akito the woman's kimono worn when she announces that she will live as a woman, and in the last chapter, he moves in with Akito in the main Sohma house.Shigure habitually wears a kimono unless he has to leave the house for business, which according to Natsuki Takaya is his way of getting into "the spirit of things" as a writer.
Along with such behaviors, it is evident in both the anime and the manga (although much more noticeable in the manga) that Shigure is extremely manipulative, and would, in reality, use anyone and anything to reach his goal. He also is spiteful, having slept with Ren Sohma, Akito's mother, to get back at Akito after she slept with Kureno.