Hatori is the doctor of the Sohma family. He grew up with Ayame and Sigure being the mature one in the group. His zodiac animal is the dragon, although when he transforms it is into a seahorse (which he is very embarrased about), because it means little dragon.

Hatori has black hair with his bangs covering his left eye. He normally wears a doctor's robe over a tux.He is very mature, calm and smart. He doesn't talk too much, and works for the Sohmas, mainly Akito.

He fell in love with Kana Sohma when she started to work for him in his office as his assitant. She had a very upbeat personality, that Tohru reminded him of when they met. On the first day they met, it was snowing and she asked him a riddle : what does snow turn into when it melts? He answered water, but she told him the correct answer was spring. He later asked Tohru this riddle and she got it correct. One day Kana found out about Hatori's secret about the zodiac and wasn't terrified at all which made Hatori happy. They started to fall in love with each other and started going out. When Hatori asked Akito if he could marry Kana, Akito got ferocious and hit Hatori hard in his left eye, although it is with a vase in the anime. Akito also yelled at Kana and told her it was her fault that this had happened to Hatori, which eventually ate her up inside. Akito then told Hatori that the only way to help her was to erase her memories. So to protect her, Hatori erased her memories of them, but never forgot the memories they spent together. Hatori is now practically blind in his left eye.

He often babysits Momiji, and is the only one who can control Ayame.