Kazuma and Kyo are the only two people in the Fruits basket series who seem to have a normal familial relationship despite not being connected by blood. Kyo possesses the spirit of the cat monster, which made his family abandon him. Kyo’s mom passed away when he was young, and his biological father abhors him to death.
All the zodiac members had it tough, but Kyo suffered the most. In a tragic sense, Kyo never had a good relationship with anyone. He didn’t get a chance to form real relationships with anyone; he didn’t get any support from the adults around him except for Kazuma Sohma. Kazuma was the one person who truly wished well for Kyo and ensured he has a bright future.
Kazuma and Kyo didn’t always have a good relationship from the beginning. Kyo was deeply hurt and he rejected the existence of everyone including Kazuma. Kazuma became the adoptive father of Kyo when no one wanted him.
Everyone wanted to lock away Kyo and treated him like a monster. It was really hurtful as a viewer to see Kyo’s father reject him after his mom passes away. Things would have been bad had it not been for Kazuma.

Kazuma runs a dojo near the Sohma estate. Kazuma and Kyo became family-like sometime after he adopted Kyo. Kazuma’s grandfather possessed the cat spirit. Even though he never met his grandfather, he knew his grandfather was locked away for life.
He met his grandfather once but rejected him because he thought he was cursed. After his grandfather passed away, he understood how badly his grandfather was treated. When he met Kyo after his mother’s death, he wanted to avoid the same ill-fated that befell Kyo. furthermore, Kazuma realized how cruel he was towards his grandfather and wanted to atone for his sins by adopting Kyo.
Interestingly Kazuma and Kyo began their relationship because of his sense of guilt and as a way of atonement. Slowly, the feelings changed and Kazuma truly began to love Kyo as his son.
He wanted the best for Kyo and took well care of him. Kyo started accepting Kazuma and he dearly cherishes his Master (Shishou) Kazuma. Although Kyo treated Kazuma well, he didn’t think of him as his father. That’s where Kyo drew the line. Kazuma was aware of it and he thought that his feeling for Kyo could be a burden for him.
"I grew to love him. Every time I saw him smile, my heart swelled. I cherished him, worried about him, and wanted him to be the happiest boy in the world. I felt like I had become his father. " -Kazuma
Kazuma took Kyo in and taught him in his Dojo. for Kyo, Kazuma was his Shisho (teacher/master), father, and family. Although Kyo never explicitly expresses his feelings more openly, the only connection he has made with the Sohma’s was with Kazuma.

Kazuma and Kyo are the definitions of family, although neither of them has any blood ties. Kazuma is a level-headed and wise adult among the Sohma’s. He is very polite and cares for Kyo deeply. Kyo is dependent on Kazuma and he supports Kyo as well.

It seems that the Sohma family had shunned Kazuma for taking in Kyo. Kazuma is protective of Kyo and showered him with love. He taught Kyo martial arts and began to teach him discipline. Kazuma helped Kyo to become independent in life and supported him to become strong.

Kazuma might have taken Kyo in to appease his guilt, but he genuinely came to love Kyo. he even as far as to confront Kyo’s father and talk some sense into him. After the accident with Kyoko (Tohnru’s mom), Kazuma knew something was bothering Kyo.
Although he wasn’t aware of the exact details, he sensed something was troubling Kyo. after this incident, Kazuma and Kyo went to the mountains to train for months.
At some point, Kyo decided that he wanted to live with Kazuma if the situation permitted. Kazuma was the only person besides Tohru who recognized and treats Kyo kindly. Others perceive Kyo as some kind of monster.
It was because Kyo was raised by Kazuma, he was not bitter and didn’t bear hatred toward others. Kazuma invited Tohru and Kyo for lunch but he is not a very good cook.

It was Kazuma who gave the rosary bead to Kyo. when Kyo’s curse was lifted he visited Kazuma. Kazuma was really happy and hugged Kyo. he felt a sense of relief and was genuinely happy for Kyo. he didn’t want Kyo to be locked up like other cat spirits.
Kazuma and Kyo truly understand each other. Their relationship slowly evolved and developed into a father-son duo. He loves Kyo and puts his need first. Kazuma has never burdened Kyo nor has he forced him to accept him as his father. He supports Kyo and his relationship with Tohru.

Trivia about Kazuma and Kyo
- Kazuma grew his hair in superstition to store good luck for Kyo. He cut his hair when he believed that he was successful in acquiring enough good luck for Kyo.
- Despite the age of 40, Kazuma looks very young. Kazuma doesn’t retire and keeps working in the Dojo even after Kyo’s son Hajime was born.
- Kazuma is clumsy and is not a good cook. He doesn’t know how to make tea either. When Tohru visits them for lunch, she offers to make lunch.
- Kazuma tried his best and made sure there were alternative plans as he didn’t want Kyo to get locked up. He wanted Kyo to have the freedom that his grandfather never had.