Supergirl has fewer great villains in the Arrowverse, but there were some serious threats that caused Supergirl big problems in the series.

Tonight, Supergirl took a page out of Smallville‘s handbook and introduced Red Kryptonite, a form of meteor rock that turns good Kryptonian boys and girls bad. Kara comes in contact with this ...

We've already seen what the green stuff can do time and time again, but now Supergirl is about to reveal what Red Kryptonite is and how it will effect our normally sweet-mannered Kara Danvers.

After being badly beaten by Reign in the 2017 finale, Supergirl began tonight’s ... who gained powers when exposed to an experimental “Kryptonite-X” and enjoyed the same flight, super ...

and Supergirl walks away. She gets dizzy for a moment, and her face gets red and glowy, but she shakes it off and flies away. A camera pan reveals a pile of red Kryptonite hiding beneath a ...

Assuming that Supergirl's Metallo runs on Kryptonite in the same way as his comic counterpart, we might want to expect more tension between Superman and J'onn J'onzz. We learned in the Season 2 ...

By Graeme McMillan Supergirl Debut Plastino - S 2013 Al Plastino ... the plotline explained away as delusions brought about by kryptonite poisoning — thus allowing a return to the optimistic ...

Metallo has always been one of Superman's most formidable enemies due to his Kryptonite enhancements, and it really might require all the united efforts of Supergirl and Superman to take him down.