Zachary Kaima'alili Kaina-Kokubun, commonly known as Zach Kaina, is a professional jiu-jitsu athlete and a black belt under Guilherme Mendes, who represents team Art Of Jiu-Jitsu (AOJ) in the sport's international circuit. Kaina is widely regarded as one of the top competitors of his generation, a reputation he earned while competing in the colored belt divisions of the International Brazilian Jiu-Jitsu Federation (IBJJF) league. Zach Kaina was born on May 23, 2002, in Oahu, Hawaii, USA, and received his black belt on December 09, 2023, from the hands of Guilherme Mendes.