While the other Arrowverse series are wrapping up, Supergirl still has a good number of episodes to go because of a 9-week hiatus. The season has been building up the Worldkillers starting with Reign (Odette Annable), then Purity (Kris Marshall) and finally Pestilence who we will finally get to meet on Monday night. Though as names goes, Reign and Pestilence sound much scarier than Purity depending on the context.
The series has eight episodes left including the one coming up this week called, Of Two Minds. We've seen images from the episode after that, Trinity, and it's possible that the image shared below by Annable and then reposted by star Melissa Benoist comes from that episode. It shows Reign and Supergirl standing side-by-side in their costumes. We haven't seen much of them together in costume. There was the big fight in the mid-season finale and then there was the fight in the subway with Purity and Reign dropped in at the end. That is a remarkably small amount of time for the main hero and the big bad to meet after fifteen episodes of a season.
Supergirl airs Mondays at 8 PM on the CW.