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

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.

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

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