Captain Boomerang (Arkhamverse)

Captain Boomerang (real-name George Harkness) is an Australian-born criminal operating within Gotham City, who specializes in throwing objects similar to a boomerang, as well as a veteran member of the Suicide Squad.

Batman: Arkham Origins
On Christmas Eve during Batman's second year as a vigilante, Captain Boomerang encountered a recently-escaped criminal and threatened him under unspecified circumstances, which resulted in the criminal requesting his friends to help him, which they refused because they initially thought it was either the cops or Batman, with Batman apprehending them shortly thereafter.

Batman: Assault on Arkham
Captain Boomerang eventually conducted several missions among the Suicide Squad. Just before his current mission to retrieve data stolen by the Riddler as well as murder him, he got into a fight in the prison cafeteria where a rival criminal attempted to kill him with a knife, only for him to throw a lunch tray at him in a similar manner to a boomerang. After being briefed about their current mission, he and the other squad members were restrained in waiting for being airdropped into Gotham City. Just before they arrived, Black Spider, a vigilante and fellow member, briefly threatened him at knife-point. Captain Boomerang had a strong rivalry with Deadshot, although he tried to be friendly with him at the bar by challenging him to a darts game.

Trivia

 * His rivalry with Deadshot was based on the New 52 version of the Suicide Squad.
 * In a behind-the-scenes featurette for Assault on Arkham during the film's development, the rivalry between Captain Boomerang and Deadshot was compared to Ocean's Eleven where Brad Pitt's character frequently attempts to kill George Clooney's character.