Kyo Sohma is cursed by the spirit of the cat of the zodiac. He transforms into an orange cat whenever he is hugged by a member of the opposite gender or if he is under a great deal of stress. The cat is not an animal in the Chinese Zodiac, but legend has it that the cat may have been included had the rat not tricked it. As a result, he and Yuki Sohma (the rat) do not get along well, since Kyo blames Yuki for all his misfortune and mistreatment, and drove him to made a deal with Akito Sohma that if he could beat Yuki, he would not be confined to the Cat's Room.
Kyo has bright orange hair and long bangs that hang over his orange-red eyes. He is near the same height as Tohru at the beginning of the series, and as the story goes on, he gets much more muscular and his build gets bigger, being very much taller than Tohru by the end of the Summer Vacation. He is defined even more from Yuki Sohma, as Kyo wears loose clothes, and dislikes tightness around his neck (similar to how a cat dislikes a collar).
He wears a bracelet on his wrist that is red and white in the manga, but dark blue and white in the anime. He turns into a bright orange cat when hugged by a girl, and when his bracelet is taken off, he turns into a monster that smells of rotting flesh, better known as the cat's vengeful spirit. He is described as 'handsome' and 'orange'. He is very well liked by Tohru Honda.
Kyo is short-tempered, competitive, impulsive and rude, but he also has a soft side that he doesn't like people seeing. He gets embarrassed quickly and is overprotective of those he cares about. Some of his classmates call him Kyon-Kyon (in episode three of the first anime, which made him angry), Kyon or Kyon-Kyon (normally by Arisa Uotani), or Kyonkinchi which means 'Lucky Kyo', normally by Ayame Sohma and Shigure Sohma who both enjoy teasing him.
An example would be that at one point Shigure pesters him about the reason he hates Yuki and Kyo stomps off to the forest, ready to cry. He also has a strong hatred for leeks, and the smell makes him sick. He also hates green onions and miso, unless it's in soup form.
Death of his mother
Kyo's mother committed suicide by jumping in front of a moving train, something his father repeatedly blamed him for. After a while, Kyo seems to believe it himself as well, but later he finds that his mother did not kill herself because she was disgusted of Kyo and what he was. She did it because she believed she doomed her family to a life of shame and ridicule for having the cat as a son. This belief was mainly reinforced by much tormenting from Kyo's father.
Taken in by Kazuma
After the death of his mother, Kyo's father rebuked him and denied to take care of his only son for he blamed Kyo for his wife's suicide. After seeing this treatment and how the last cat, Kazuma's grandfather, was treated by the family, he took Kyo in.
After becoming Kyo's adoptive father he began training Kyo in martial arts to perhaps teach him discipline and to help Kyo become stronger in his life knowing it will be so difficult being cursed by the cat.
Meeting Kyoko Honda
As a child, Kyo met Kyoko one day while sitting outside near the Honda house. Kyoko was very curious about his hair color and proceeded to talk to him. He was very distant at first for he was not used to that many people wanting to associate with the cat. And, after telling him her name, was embarrassed that it was so similar to his. But Kyoko's persistence broke through as she would do the talking and all he had to do was listen.
She continued on about how cute her daughter was, showing him a photo of Tohru and asking if he thought so too. He agreed in silence that she was. After that, she went on to say how strong Tohru was dealing with her father's death and letting her mother take her time; even though Kyoko was in shock during most of that time.
After more meetings, Kyo would spy on Tohru and wish to speak to her. And then one day, while near the house, Kyoko lost Tohru while walking and became hysterical. Kyo tells her to wait at home and then promised, as a "man", he would bring her back safe at home. After passing Yuki he lost his hat as he was in a determined hurry to find her. Yuki takes the hat, puts in on, and walks around searching for Kyo and instead he finds Tohru.
Kyoko is then seen searching for Kyo and tells him that she was found by a boy with Kyo's cap on. This enrages Kyo and he flees from Kyoko, hurt from not being to one to "save" her daughter.
Before Summer Vacation
When his Juzu beads are removed, he turns into a grotesque monster with a revolting scent. After Kazuma Sohma removes his beads, Tohru Honda chases after him. After being injured by Kyo, who scratched her, she tells him that he's scaring her. But she also says that she wants them to be together, with Yuki Sohma watching the whole time (in the anime). He changes back into a human and tells Tohru that his mother lied and told him that she loved him, but Kyo knew she was afraid. He said that he had no problem with his mother being afraid of his true form. Then he hugged Tohru and asked, "Why?" He changed into a cat and Tohru carried him home.
During Summer Vacation
After Summer Vacation
It is not known whether Kyo really took over Shishou's dojo.