Oliver Queen, known as Black Arrow, is one of the main antagonists of the Arrowverse 2017 film Crisis on Earth-X (the other being Eobard Thawne).
He is the Nazi version of Earth-1's Oliver Queen, The final Führer of the New Reich, and is the husband of Overgirl. He hails from Earth-X and arrives on Earth-1 as part of an invasion force. Despite their plans of conquering Earth-1, his main motivation is to capture Supergirl in order to steal her heart and implant it into his dying wife.
Born on Earth-X, a world where the Nazis won WWII, Oliver was raised indoctrinated into the attitudes of the Third Reich. As every citizen on Earth-X, Tommy did not go to school but instead was part of youth groups and subjected to military training from an early age on. Like their Earth-1 counterparts, Oliver and Tommy Merlyn became best friends.
He eventually fell in love with the kryptonian refugee Kara Zor-El, known as Overgirl, and eventually married her. The two became a powerful couple in the Third Reich.
Crisis on Earth-X
He alongside Thawne, Overgirl and other Nazis come to Earth-1 to attack the resident heroes during Barry and Iris' wedding.
At the end, he is saddened of the death of his wife and tries to shoot Earth-1 Oliver, but the latter shoots first.
Barry Allen/The Flash (attempting killer)
Oliver Queen/Green Arrow (killer)
Kara Danvers/Supergirl (attempting victim)
Sara Lance/White Canary
Jefferson Jackson/Firestorm (indirectly attempting victim)
Felcity Smoak (attempted victim)
Caitlin Snow/Killer Frost (prisoner and attempting victim)