Green Arrow first joined the Justice League during the team expansion that followed the Thanagarian invasion of Earth. During his first mission with the team, he helped Green Lantern, Captain Atom, and Supergirl stop an atomic-powered juggernaut called Brimstone during a rampage through the countryside region of China. He soon took notice of Black Canary, who was also admitted to the team at that time, and decided to stay on just to get to know her better. Eventually, Green Arrow helped Black Canary rescue Wildcat from his addiction to fighting in Roulette's Meta-Brawl arena against meta-humans. Black Canary offered to fight Wildcat on the grounds that Roulette would ban him from future participation in Meta-Brawl, which she accepted; however, Green Arrow knocked Black Canary out with a ga