Kozume Kenma is the brain of Yinju, and Kuroo Tetsurou is the meridian and blood vessel of Yinju, connecting the brain and blood, so that the brain can exert its maximum potential, and the blood can flow smoothly and supply oxygen.
Kozume Kenma exudes a sense of maturity in her childishness. "Naive" and "mature" seem to be two incompatible words, but they are perfectly reflected in him.