In this image that has been circulating from a supposed past draft of BvS, it looks as if from the dialogue there is a reason to believe Metallo and possibly a form of Brainiac are villains alongside Lex.
It would appear that Lex is trying to create a drone army and develops Metallo using Corben as a "host" to fully adapt the Kryptonian technology as the current understanding of AI is limited. Brainiac appears to make computer contact with Lexcorp.
Perhaps this means Brainiac will help Lex construct Metallo for the purpose of perfecting the process and ushering in a physical body for Brainiac, along with a drone army that he could possibly take control over from Lex.
Lex may in fact be taking the superhero "military development" plot device in BvS. Could that mean Corben is a former soldier adapted to become Metallo? Interesting theories can be developed from this script snippet.
[image removed]