Billy Kane/Story

Fatal Fury
When he was a young teenager, both Billy and his sister were orphans in London. Life was hard for them with Billy having to steal food to feed Lilly. They were spotted by Geese Howard, who was on a business trip in Europe. Seeing himself in the two orphans, he takes them in after he sees Billy's skill with his bo.

Years later, Billy became the crime lord's, right-hand man. Geese would hold The King of Fighters tournament every year with Billy as his champion. Billy was undefeated until he was beaten by Terry Bogard, who moved on to defeat Geese. Billy then swore revenge against "The Lone Wolves" Terry, Andy Bogard, and Joe Higashi.

After his boss' supposed death, Billy went back to England with his sister. In order to adequately provide for her, Billy continued his life of crime and joined Wolfgang Krauser. Although it seemed like he was loyal to the nobleman, Billy was actually working undercover to search and destroy Geese's impostor (the latter detail was retconned in Fatal Fury Special). His additional order was to overthrow Krauser. He succeeded in the former and continued to serve the real Geese until the latter's death. Later, in Dominated Mind, he was brainwashed by White to serve him.

Billy's whereabouts during the 'Garou: Mark of the Wolves' timeline remain unclear. In his development blog for 'KOF: Maximum Impact 2', Akihiko Ureshino states that he doesn't know about Rock's mother or the true inheritor of Geese's legacy, but hints that it would most likely conflict with Terry. Billy's scenario in this game explores his personal take on the character's actions in the yet to be released Mark of the Wolves sequel. He particularly wanted to emphasize Billy's anger and bitterness, which is later found in the cellphone novel.

The King of Fighters
In The King of Fighters series, Billy's biography is identical, except Geese isn't dead in this continuity. As a result, he is consistently following Geese's orders in all of his appearances.

Orochi Saga
In 'The King of Fighters '95', he became one of the members of the Geese organized Rival Team, which included Iori Yagami and Eiji Kisaragi. His orders were to get revenge for Geese's defeat by the Bogard siblings. In his team's ending, he was badly beaten by Iori in the tournament's climax. In the 1996 tournament, Billy stayed on the sidelines and saved Geese's life from a sniper sent by his teammate Mr. Big. The following year, he teamed up with Blue Mary and Ryuji Yamazaki to investigate Orochi and the effects of Orochi blood in humans, such as on his former teammate turned personal enemy, Iori.

Tales of Ash
Although he is often paired with these two in many appearances, Billy didn't officially enter another tournament until 2003 with Gato and Yamazaki. His personal orders from Geese were to keep a close eye on them, especially Gato, since his father could be tracking him. Remembering the broker's attack on Geese after their last team up, Billy remained hostile to Yamazaki throughout the tournament. In their team's ending, the duo fight to an unknown conclusion.

Shun'ei Saga
When the new tournament is announced, Billy's asked to participate with his boss and a new member, Hein.

KOF: Maximum Impact
Billy's life in this timeline is a mix between his Fatal Fury and KOF counterparts up until Real Bout Fatal Fury and The King of Fighters 2003.

In KOF: Maximum Impact 2, Billy moved back to the countryside of the United Kingdom with his young sister after Geese's fatal showdown with Terry. Although he spent his days in tranquility, Billy internally struggled with his desire to fight and stay with his sister. Once he hears that the Meira borthers, Alba and Soiree, were running South Town, Billy embarked from his home to defend his old boss' legacy. He additionally wants to settle his differences with Terry, which is explored in detail during his and Terry's story mode.

The second episode of 'The King of Fighters: Another Day' also explores a possible encounter Billy would have if he met Geese's son, Rock.