Warning: spoilers ahead for Batman/Superman #18!
The DC universe's 'reverse Lex Luthor' couldn't be more perfect in a new comic. Batman/Superman #18 reveals that there is an alternate Lex Luthor that the heroic duo is up against. This Lex is not pulling any punches for anyone - himself included.
Batman/Superman #18 by Gene Luen Yang and Ivan Reis tells three stories that intertwine, blending together three different realities. Batman from a world without Superman and Superman from a world without Batman have joined forces to fight foes and save their worlds after their realities collide. However, they aren't the only ones that can cross realities and change them. One villain has long been ahead of them, trying to shape reality at the cost of another - Lex Luthor - all for the sake of survival.
This issue fully reveals what Martha Wayne and Dr. Atom's plans have been and what their partnership entails. The Lex Luthor of the World of Tomorrow has taken up the name of the Unknown Wizard. He has been captured by the villainous duo, who plans to ship him off to the World of the Knight to be experimented on. Martha and Dr. Atom have been sending numerous villains over, though their reasoning - and much more - has come to light. Dr. Atom is the mastermind behind the plan and as soon as Superman is able to, he takes off his mask. As it turns out, Lex Luthor's worst enemy is actually himself, literally. Dr. Atom is revealed to be a Lex Luthor from a completely different reality - and he had no problems sending his alternate self off to a worse reality to be experimented on.
Reverse Luthor - formerly Dr. Atom - came from a different reality that was destroyed by this series' bigger baddie: Autuer.io. According to this version of Lex Luthor, he is actually trying to save the World of Tomorrow from Autuer.io, the way he has destroyed other realities. While Lex's actions could be seen as a good thing from some perspectives, the cost he is paying to do it is very high. Lex Luthor always looks out for number one - even against himself.
Reverse Luthor reveals just how far the supervillain is willing to go to achieve his goals and survive. He is willing to sacrifice alternate versions of himself if it means his own identity is safe in the body he is acting within. This villain won't partner with himself and will even go so far as to encourage his own kidnapping if it has enough benefit. This fits exactly with Lex's motivations and tendency to think highly of himself at the detriment of others. DC has truly made a perfect reverse version of Lex Luthor in this series.