Animal: Rabbit
Momiji comes across as cute and perpetually cheerful, but there's real darkness underneath—a tough family situation he masks with constant smiling. His tendency to whine and cry gets on Kyo's nerves constantly. Despite looking younger than his actual age, he's only a year behind Yuki and Kyo; he's actually the same age as Hatsuharu, which surprises most people.
He's the rabbit of the Zodiac and comes from money—one of the wealthier branches of the Sohma family. His father is Japanese, his mother German. He has a younger sister, Momo, who doesn't know he exists; their mother's memories of Momiji were deliberately erased to protect her sanity.
What's interesting about Momiji is how emotionally intelligent and resilient he actually is beneath that bubbly exterior. He bonded with Tooru almost instantly, didn't care about the whole Zodiac curse thing, and straight-up hugged her when they met properly—which horrified Kyo. He's not shy about wearing the girls' uniform to school either, usually pairing it with short shorts instead of a skirt, much to Kyo's visible discomfort. They'll sometimes run into each other when Tooru's working, and he'll help her clean up; he even covered her chores once when she was sick. He's developed genuine feelings for Tooru and tends to crossdress pretty regularly.
Content compiled by AnimeList.moe from publicly available sources.