Momiji Soma is a member of the Soma family who is possessed by the spirit of the Rabbit from the Chinese Zodiac. He is fifteen years old at the start of the series, though his youthful appearance and small stature often cause others to mistake him for being much younger. He is actually only one year younger than Tohru Honda and the same age as Hatsuharu Soma. Momiji is the son of a wealthy branch of the Soma family; his father is Japanese and his mother is German. He also has a younger sister named Momo, who has no knowledge of his existence.

Momiji’s background is marked by deep personal tragedy. Because his mother could not bear the reality of the Zodiac curse, her memories of Momiji were erased when he was still very young. This left him estranged from his own mother, who now treats him as a stranger, and his father became his sole caretaker. Momiji copes with this rejection by adopting an outwardly cheerful, energetic, and playfully dramatic demeanor. He is often seen smiling, laughing, and making others laugh, and he has a tendency to wear the girls’ version of his school uniform, much to the dismay of his cousin Kyo Soma. Despite his seemingly carefree surface, Momiji is deeply insightful and emotionally resilient. He is fully aware of the pain he carries but chooses not to burden others with it, instead using his lightheartedness as a shield.

Momiji’s motivations are rooted in a desire for connection and acceptance. He genuinely wants to be happy and to make others happy, and he values the bonds he forms with those who see him for who he truly is. He is one of the few Zodiac members who has come to terms with his curse, and he does not resent his spirit possession. This inner strength makes him a stabilizing presence among the Sohmas and a natural bridge between the family and outsiders, particularly Tohru Honda.

In the story, Momiji serves as a recurring supporting character who reveals the hidden suffering that underlies the apparently cheerful lives of the Zodiac members. He is often the one who gently exposes the painful truths that others try to hide, especially through his own example. He develops romantic feelings for Tohru, whom he admires deeply for her kindness and empathy, but he eventually recognizes that her love for him is purely familial. This unrequited love is a source of sorrow that he bears quietly, though it occasionally surfaces when he urges others, particularly Kyo, not to waste the love they have been given.

Momiji’s key relationships include his warm but ultimately sad connection with Tohru, his complicated dynamic with his mother whom he visits secretly just to see her from afar, and his friendly bonds with other Zodiac members such as Yuki Soma and Hatsuharu Soma. He frequently annoys Kyo with his playful antics, but there is underlying mutual respect. He is also protective of his sister Momo, even though she does not know he is her brother.

Throughout the series, Momiji undergoes significant personal development. He learns to confront his own pain directly rather than always deflecting with humor, and he grows into a young man capable of expressing his true feelings, including anger and sadness, when the situation demands it. His ability to transform into a rabbit is a central part of his identity, and he uses it both for practical purposes and as a reflection of his own gentle nature. Notably, he is described by the author as being the most comfortable among the Sohmas with his spirit possession and the most successful of the boys in terms of his personal outlook. His notable abilities include his emotional intelligence, his skill at reading others, and his remarkable resilience.