Takato is one of Kazu's best friends
Kazu and Rika had a continually made fun of each other
Kazu is in awe of Ryo due to his status as the Digimon King. During the battle against ADR-06, the two work together and Kazu's Guardromon even saves Justimon's life earning Kazu Ryo's thanks, causing him to be very happy.
Kazu and Kenta often do their jokes together, and are rarely seen separately. Kazu is more confident though, while Kenta just follows Kazu's lead. He was also seen blackmailing Kenta by threatening to reveal embarassing secrets about him on one occasion.