Reign and four other aliens were taken as infants to a space station research facility by a team of Kryptonian scientists. Here Reign and her fellow aliens were improved and bestowed great power through Kryptonian science to make them like the Worldkillers of old. Reign and three other new Worldkillers awoke to find the space station severely damaged with no one alive and the fifth Worldkiller missing. They made it their quest to find their homeworlds and, using data from the space station, they found the trail led to Earth.
Reign was created by Michael Green and Mahmud Asrar to be among Supergirl's first villains after the New 52 reboot. It has been speculated that as a worldkiller, she is akin to Doomsday and that it was Doomsday who was the fifth, missing worldkiller.
Reign will be part of the main cast as the primary antagonist in the third season. She will be portrayed by Odette Annable.
At the end of season 2, a flashback shows a third pod being sent from Krypton to Earth, after Kara´s and Kal´s pods, with Reign on it.