The Supergirl television series has developed the Worldkiller concept beyond its brief use in the Supergirl comics.
The main storyline of Supergirl’s third season has pitted Kara Zor-El against Reign – one of the living Kryptonian biological weapons called Worldkillers.
The Worldkillers first appeared in DC Comics New 52 Supergirl series and were co-created by American Gods producer Michael Green and writer Mike Johnson.
Supergirl was able to repel the Worldkillers and forced them to retreat, with Reign swearing that she would fight Supergirl again someday.