Usually an Enigma, he rarely expresses himself. But in G Rev he does express himself during his intense battles.
This is one such scene where Kai got so worked up over something. Such as in this episode when Kai fights Brooklyn for the first time and Hitoshi taunts Kai about his intention to join BEGA. Kai evidently regards Takao's and his battle as something akin to a treasure and valuable.
He goes absolutely ballistic when Hitoshi casually comments on his and Takao's battle calling it a "mere obsession". Hitoshi's choice of words ticks him off successfully. His expression twists and his voice gains an edge. His words and expression ooze dislike at Hitoshi's non chalant words.
It's like he's questioning Kai's thoughts feelings and his dedication he put forward in his pursuit of Takao. It's outright disrespctful towards someone's hardwork and feelings.
