Hwa Jai/Story

Past
A former Muay Thai champion, he was defeated by Joe Higashi. Vowing to overcome the Tiger Kick with his own Dragon Kick, he was convinced his style should be more violent and brutal to defeat his rival. Killing thugs as he trained, he was eventually shunned by the martial arts world. Noticing Geese Howard's strength, he became his subordinate soon after.

Fatal Fury: King of Fighters
During the King of Fighters tournament, he seeks to triumph over Joe for all the despair his rival caused him since his loss. However, after Joe defeats him again, he realizes that he had lost due to his weak mind and spirit. Reformed, he leaves Geese's employment and becomes good friends with Joe and supports him as Muay Thai's unbeatable champion.

He is one of the many fighters beaten by Wolfgang Krauser in Fatal Fury 2. Joe avenges Hwa Jai in his ending.

The King of Fighters series
Hwa Jai's past employment with Geese is elaborated to have started due to him winning a tournament in Japan. After cutting his ties with Geese, he went back to his homeland. Despite what earlier accounts have implied, Hwa Jai hasn't made a comeback to the Muay Thai ring since then.

The King of Fighters XIII
Both he and Raiden were called to South Town by Kim Kaphwan, who believes that they are wasting their talents and need to be "reeducated". Though Hwa Jai replies that he has already abandoned his "evil ways", he is convinced by the masked wrestler that entering with the famous Kim might be a good way to revitalize his reputation to the public. Hwa Jai also wants to use this opportunity to take another shot at his rival, Joe. He and Raiden secretly proven to Chang Koehan and Choi Bounge that they are better on fooling Kim than Kim's first teammates.

The King of Fighters XV
Although he did not participate in the fifteenth tournament, he was present with Terry Bogard and Andy Bogard to visit Joe, who is currently in a hospital after trying to go on a date with Lilly Kane, and her brother "intervened".