Board Thread:Supergirl discussions/@comment-28109177-20180619030449

Warning: Potential Spoilers Ahead 

I won't spoil too much, this is just my theory. Okay, so we all saw the finale, Reign is defeated, Sam survives. Reign was defeated using the Harun-El and Supergirl and Samantha were able to defeat Reign once and for all, however there was a complication revealed towards the end, when Kara touched the Harun-El With Sam, something smokelike was released into the air and at the end it was revealed to be ANOTHER Kara that was born.

Which leads me to my theory, this villian is Dark Supergirl from the Supergirl New Earth Comics in Volume 5, In the comics Dark Supegirl was created by Lex Luthor by using Black Kyptonite.

Black Kyptonite is a substance used to split Kryptonians between their good in their bad sides. Black Kryptonite was first introduced in the DC TV universe in Smallville and later appeared on Supergirl but renamed as "Harun-El" this is what split Samantha and Reign and it seemingly created another Supergirl.

So, my conclusion, this is the next big bad. To be honest, I knew this would happen as soon as Harun-El was revealed. 