Momiji Sohma/Relationships

Father
Even though Momiji’s father promised to love Momiji twice as much to make up for his mother forgetting him, he built a new family built on Momiji’s absence and even forbade him from interacting with his mother and sister. In spite of this, Momiji still appears to respect him and does not hold any ill feelings towards him, as he is able to understand his situation. While Momiji does feel left out, he doesn’t want to ruin his father’s new-built happiness and therefore goes along with his wishes.

In Fruits Basket Another, Momiji has taken over his father’s business, so it is implied that father and son have grown closer throughout the years.

Mother
Even though Momiji’s mother completely and utterly rejected him, as well as willingly chose to forget all about him, Momiji loves her deeply. Momiji’s philosophy on life is that he doesn't want anyone to forget a single memory no matter how painful it is, but agreed to make his mother forget about him since he only wanted her to recover. Throughout the years, Momiji has continued watching over his mother from afar in secret and holds her in high regard, harboring great pride in his German heritage through her.

Even though Momiji feels left out and describes his mother and the rest of their family as a distant place he will never be able to reach, he is happy and fully content with just being able to normally converse with her and see her smile, which she couldn’t do when she still had her memories of him. It is indirectly through her, among many other factors, which leads to Momiji wanting a loving family of his own in the future as well.

In Fruits Basket Another, it is implied that she knows that Momiji is her son since Momo is aware that Momiji is her older brother, but their relationship remains scarce.

Momo Sohma
Even though she isn’t aware of their familial bond, Momiji loves his younger sister, Momo, dearly, and prioritizes her happiness over his own. Just like with his mother, Momiji has always been watching over Momo from afar, and is proud of her growth. What Momiji doesn’t know, however, is that Momo loves and admires him as well, and due to their resemblance, wants him to be her real older brother. The reason why Momo started playing the violin in the first place is because wanted to find an opportunity for them to play together. When Momiji found about Momo’s wish, he was so touched that he broke down in tears. However, knowing of his father’s insisting that he shouldn’t interact with his mother and sister, Momiji, while he does wish to be a part of their family, is content with simply continuing watching over them from afar.

In Fruits Basket Another, it is revealed that Momo now knows that Momiji is her older brother. Momo respects and loves her older brother, and since she is his personal assistant and close to Momiji’s daughter, Mina, they are implied to spend a lot of time together and seem to have gotten closer throughout the years.

Mina Sohma
Although there haven’t been any on-screen interactions between the two, Momiji is known to be a loving and doting father towards his daughter, Mina, since she respects him greatly and wants to follow in his footsteps. Whenever Momiji returns home from business trips, Mina is always ecstatic and wants to greet him as fast as possible.

Tohru Honda
Ever since the beginning, Momiji has been very fond of and affectionate with Tohru; including kissing her when they first meet, and often hugging her, holding her hand, and generally initiating plenty of physical contact with her. While Tohru is initially overwhelmed by his extremely energetic personality, their friendship strengthens greatly as they continue spending more time with each other and realizing that they are very much alike and in sync. Momiji is relaxed and comfortable in Tohru’s presence, especially since Tohru is an outsider but still very accepting of him and is glad to have met him despite him being cursed.

Because of this, Momiji comes to trust Tohru a lot and she is the first person he willingly confides to about his family situation. And because they both have experienced painful things regarding their mothers yet remain positive in spite of it, Momiji and Tohru develops a deep understanding and admiration between each other and thus becomes a source of comfort and support for one another. It is thanks to this understanding that Momiji becomes the first one to indirectly admit that while Tohru is selflessly kind - sometimes to a fault - he doesn’t think she is foolish at all, which even ends up changing both Kyo and Yuki’s perceptions of her selfless nature.

Thanks to Tohru’s continual kindness, acceptance and support, Momiji eventually ends up developing romantic feelings for her. While Momiji does occasionally let himself be taken care of by Tohru, he cares about her deeply, always encourages her happiness, is very helpful towards her since he is able to read her pretty well, and looks after her whenever she forgets to look after herself. At one point, he admits to Kyo that he can’t help but to love Tohru as much as he does, and even compares them to a married couple at another point. His feelings towards Tohru are so strong that he willingly stood up against Akito - the ”God” he is normally unable to disobey and is afraid of - and even let himself get berated and punched by her in order to protect Tohru. Momiji also mentions that despite everything he has gone through, he is able to be happy and smile because Tohru is there to cry for him.

When Momiji enters his growth spurt, he makes his romantic feelings towards Tohru more clear. He admits that even though he enjoyed getting away with certain things when he was still small, he is glad that he grew up, because there was a chance that he would be taken more seriously by her now. Momiji also tells Kyo that if he were to ever give up on Tohru, he would steal her away from him. However, Momiji never actually tells Tohru about his feelings because he knows that she is in love with Kyo. When his curse breaks, Momiji is saddened because he knows that Tohru would be much happier if Kyo’s curse broke and because he would still never have a shot at Tohru’s heart. Despite his emotional turmoil, Momiji gradually moves on and becomes supportive of Tohru’s relationship with Kyo, as her happiness is his happiness.

Kyo Sohma
Momiji considers Kyo a close friend. He is fond of Kyo and regularly displays affection towards him and always invites him to events, and isn't particularly bothered about his role as the Cat. On the other hand, even though Kyo is annoyed at Momiji's happy-go-lucky and unpredictable personality, and that he wears the female school uniform (he is not afraid to show his disdain or annoyance towards him by smacking him or hitting him), they can get along quite well and Kyo does not seem to be bothered by his company and when Momiji is affectionate with him.

Later in the series, when both of them realize they love Tohru, their relationship becomes quite tense. Momiji confesses that he is jealous of Kyo and knows that Tohru would be happier if Kyo's curse broke instead of his own. He is sly and teasing towards Kyo as well, such as telling him that he would grow to be taller and more handsome than him, as well as taking pictures of Kagura hugging to showcase his "fickleness". Momiji also urges Kyo to act on his feelings towards Tohru, making it clear that he would steal Tohru from him otherwise. When Kyo later gets together with Tohru, he is shown to "apologize", but Momiji tells him it's fine.

Hatsuharu Sohma
Hatsuharu and Momiji share a very close and brotherly bond. They are the same age and are polar opposites, yet they don't let that get in the way of their friendship. They are in the same class and spends a lot of time together, both outside and in school. Momiji is affectionate with Hatsuharu and vice versa, and unlike other people at school, Hatsuharu did not mind when Momiji wore the girls' school uniform, insisting that if he feels comfortable in it, he should wear it. Hatsuharu also cares for Momiji and looks after him, and can sense it when something feels off about him; this is confirmed when Hatsuharu suspected that something was off with Momiji, and he actually had his curse broken. After their curse is broken, Momiji, Hatsuharu, and Rin seem to have become very close, as they are shown to report their daily lives as well as their plans for the future to one another.

Hatori Sohma
Momiji has been close to Hatori for his entire life and is very affectionate with him. He is comfortable in doing as he pleases in Hatori's presence, and gets along with him well. Due to the lack of adult figures in Momiji's life and feeling responsible for wiping his mother's memories, it is possible that Hatori stepped in Momiji's life. It is mentioned that Momiji often goes over to Hatori’s for meals and that Hatori often checks up on him as well.

Akito Sohma
It is unknown how Momiji exactly feels about Akito. During the beginning of the series, Momiji was one of the few people Akito hadn't personally hurt. However, Momiji is one of the Zodiacs that Akito dislikes the most, which Momiji is well aware of but doesn't mind. At the same time, Momiji seems to fear Akito; though he doesn't show it, and can't disobey Akito due to her being the "God". However, he is calm in her presence and even tries to understand her at one point, and he also stands up towards her in order to protect Tohru. In response, Akito beat Momiji which later caused the young boy to break down in tears.

For a long time, they have a tedious relationship with no interaction, but when Momiji's curse breaks, she resorts to desperately begging Momiji to not leave her. However, Momiji, feeling no connection to Akito with the curse's shackles gone, is baffled to realize how a weak and pitiful person such as Akito could bind him and instill fear into him in the past. Despite Akito's begging, berating words, and her violent behavior towards him, Momiji decides to become independent from her and live as a normal human member of society. Although it is unknown if they truly reconciled, it is shown that Momiji shows a positive attitude when Akito later changes for the better and vows to make amends, and even gives her advice and tells her the story of the foolish traveler so she would be inspired to visit Tohru in the hospital. Akito also gave Momiji and the other Zodiacs their freedom in the end.

Isuzu Sohma
Although there wasn't much interaction shown between the two at first, they are shown to have become friends towards the end of the series. Momiji is comfortable enough to confide in Rin about his wishes about the future, and his feelings towards Tohru.