Discover how Supergirl's bizarre first kiss with Poison Ivy unveiled her immunity to synthetic Kryptonite, a power even Superman lacks.

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.

Black Kryptonite is one of the deadliest forms of Kryptonite in existence, and now it's back and worse than ever.

Supergirl (2025) #3 just reintroduced Satan Girl with the use of Black Kryptonite, which not only brings her back into continuity, but makes her one of Supergirl’s most dangerous villains.