Kazuma Sohma (草摩 籍真 Sōma Kazuma) is a master of martial arts who runs a dojo near the Sohma family compound, where he teaches several of the younger Sohmas, including Kyo Sohma, Kagura Sohma, Yuki Sohma, and Hatsuharu Sohma.
Although Kyo calls him Shishou (meaning "Master"), he states that he doesn't want to make his students address him by such. Instead, most of his students call him Sensei, meaning "Teacher". His daily routine is taken care of by his assistant at the dojo, Kunimitsu Tomoda.
Unlike Kyo's biological father, Kazuma is very kind and loving to his pupil and adoptive son. Despite raising him as repentence for being cold for the previous cat (his grandfather), he has come to genuinely care about Kyo. He has displayed his wisdom and determination to Kyo and the rest of the Sohma family in the duration of the series. He was even willing to defy the rest of the family in order to keep Kyo from meeting the same lonely fate his grandfather faced and give him a happy life.
Relation with the Cat Spirit
When he was a child, during their only meeting, Kazuma was mean to his grandfather simply because his grandfather was cursed by the Cat. Once, when he was still a child, his grandfather offered him a candy but he rejected it, saying it is cursed. To make amends, after Kyo's mother died, he took in and raised Kyo, the current Cat, as his foster son, and has come to think of him as his own son.
Before Summer Vacation
Kazuma thinks well of Tohru Honda and hopes her love for Kyo is sincere, and not based on pity like his grandmother's was towards his grandfather; both to test Tohru's feelings and to show Kyo he can be accepted despite his curse, Kazuma forces Kyo to show Tohru his true form.
After Summer Vacation
After Rin is hospitalized the second time during the series, he takes her in to recuperate so that she does not have to live inside the family compound, which he has done before. Saki Hanajima is working at Kazuma's dojo as a chef and it is implied they are in a relationship.