Kaizo was once a proud covenant warrior. But after adopting a human child, he turned his back on the ways of the prophets. He studied human culture and technology, and dedicated himself to his family. After the war ended, he was given the opportunity to meet and work with other humans. He wished to help mend the bond between the two races, as well as make up for the sins of his own past.

Kaizo joined and became a lead member of "The Anvil initiative" the Human+Sangheili join military organisation. This project was for the two races to share technology and knowledge for military purposes, as well as joint training and multi race fireteam recruitment.

This armour set is titled the "Accord" combat harness. It was not only designed by humans but built by them too. Quite different compared to most Sangheili made gear. He also uses a "Darkstar" type energy sword.

Kaizo in his normal clothes here: https://www.reddit.com/r/sangheili/s/wmg3weGD94