Lex Luthor, who haven't you been? Mad scientist, criminal kingpin, billionaire industrialist, white collar crook, government agent, real estate mogul, President, wastrel son. Far more often than Superman, Lex's villainy is reinvented every generation or so to reflect modern fears. So what fear will this archenemy of archenemies personify in the Drewniverse?
The fear of change.
Lex Luthor represents the toppling of old hierarchies, the replacement of decaying systems with new, the painful progress of mankind. He does not want to rule the world, he wants to tear it apart and rebuild as something better. The ends justify the means, so who cares if a few rules are broken or a couple of thousand people die for progress? Lex believes that though he may be called a monster today, he'll be regarded as a savior by history.
For our Luthor, I'm drawing on a variety of sources. The DCAU Lex Luthor is central, of course. I'm not sure I can imagine his voice without hearing Clancy Brown. I dislike the wacky real estate schemes of the Donner-based movies, no matter how many Oscar winners take the role. Sleater-Kinney's One Beat in his song. From the real world, we're drawing from change-the-world moguls like Steve Jobs, Bill Gates, Mark Zuckerberg and others who have changed the way our lives work through their products or innovations.
Luthor's early rise to fame should pretty much mirror Zuckerberg's - genius kid/young adult produces society changing product, becomes super rich. Sure, said kid stepped on a lot of toes and stood on a lot of shoulders to produce that product, but so what? Should he have just sat back and let all these disparate factors slowly congeal into something of value or should he have taken the reins and Made It Happen? Our Lex's genius is synthesis and systems. He can look at an existing system and easily identify flaws and inefficiencies. He can take seemingly unconnected technologies and combine them into something new. Lex is a scientist, sure, but he's a closer. You won't find him in the lab working on fundamentals or testing out some new theory, you'll see him in the lab taking the work of others and combining it in new and often terrible new ways.
Were it not for the arrival of Superman, Lex Luthor would have advanced humanity far faster than it would have done itself. This is why he hates Superman. It's not just that Superman's arrival on the public stage happened to coincide with a world-changing announcement from LexCorp, meaning that pictures of a man lifting a car above his head shoved stories of a cure for HIV (or something) far below the fold. It's that Superman represents this sort of folksy, traditional Golden Age wishful thinking that Luthor thinks is holding humanity back. These are not simpler times and we should not waste energy idolizing something who represents them.
That Superman is so idolized enrages Luthor. Take what Anthony Bourdain wrote about Rachael Ray and multiply it by a thousand. In Luthor's mind, people look at Superman and say, "I wish I could do that, but I'm not special like that, so I won't even try." It's not just a give a man a fish vs teach a man to fish scenario. Luthor not only wants the man to want to learn how to fish, but to learn how to make his own fishing rod and then improve on the whole process. Superheroes make mankind complacent.
What's more, superheroes tend to reinforce the established order of things, a total waste of their potential. They have capabilities lightyears beyond even what Lex's technology can produce and they spend their time fighting crime and rescuing people? Why? If saving lives is so important, why don't you go after the root causes? Gotham City sits near a major fault line, so don't wait for a huge earthquake, move the damn city. Stop playing cleanup and design a system that cleans itself.
Of course, Lex Luthor does not hate the idea of all super-powered people, just those that were born or stumbled in to their power. Those that reached out and took power are just fine in Lex's book. They represent that next step of humanity, those willing to take their future into their own hands. It does disappoint Lex to see these talents so wasted by society. Imagine what Dr. Victor Frieze could do if he did not have to resort to crime to finance his research. So through a labyrinth of shell companies and government contracts, Lex does his best to see that these geniuses get the funding and support they need.
In this way, Lex Luthor is really the Father of the Modern Age of Heroes. Most, if not all, of the science based heroes and villains of the Drewniverse owe their existence in some way to Lex Luthor. Bizarro? Created in a LexCorp's subsidiary lab. Power Girl? Created in association with S.T.A.R. Labs under government contract. Superboy? LexCorp again. Metallo? A Luthor Genius Grant got Dr. Vale most the funding for his work. The Atom got access to white dwarf star material from LexCorp. The list goes on before we even get into the 'accidental' creations like Parasite or Livewire or the Bang Babies whose powers stem from improper handling of LexCorp materials. Even Batman has some toys that owe their origins to WayneTech/LexCorp joint ventures.
Lex is interested in business only because he knows it still takes money to fuel innovation. He takes no interest in laws or regulations because he knows they only hold back exceptional people like himself. Since money and power helps him get around these lesser laws, he covets both, but will be happy when the day comes that he doesn't need them, when the world just recognizes that he is right and gives him whatever he needs. He sees no hypocrisy in putting himself ahead of the average person. Where he leads, others may follow, while they can only watch where Superman goes.
Luthor only comes into conflict with heroes when they stand in his way, which they do all too frequently. That probably has something to do with the fact that the law can't or won't touch him. Since the discovery that aliens walk among us, he has teams spread far and wide searching for alien technology. He doesn't truck much with magic as its use is not universally available to everyone, just homo magi (although, if some gene therapy that simulates homo magi qualities in homo sapiens could be developed...). He has no interest in running for office - why spend all that time and money for a demotion? When needed, he has access to bleeding edge technology and host of henchmen (Mercy!), hirelings, and mercenaries.
Over the course of the larger story arc, Lex Luthor will be right more often than not. Scattered through the various titles, we'll see mentions of the amazing advances LexCorp is making: cures for diseases, new energy sources, transportation innovations, communication technology, all that good stuff. Fighting Lex should lead to an internal conflict on the part of the hero. How can Jamie Reyes bring down the man who pioneered the asthma treatment that makes it so his sister can breathe without worry? Sure, Superman can bust into one of LexCorp's top secret labs, but to get there he'll have to go through the facility where they make Ma Kent's heart medication. This is the sort of thing that will wear down Superman's faith not only in humanity but in his own purpose. "So far this year, Superman, you have saved 135,686 people by catching airplanes and punching criminals. Meanwhile, I have saved over 250,000 by authorizing new research and signing a few checks. Do you really want to cart me away? You can lock me up and let me rot in prison, but I assure you the world will rot too."
This is the change the superheroes fear - that in a new world, there will be no need for them, that people would prefer to be lead by a callous and uncaring sociopath like Lex Luthor. He says he wants to help all of humanity better itself, but it's pretty clear he's willing to rip out all that makes us human to do it.
Lex won't get his own title - he's way too busy for that - but he will have features in the short-form oriented title, All-Star Villainy (13/52), that will focus on 4-6 issue storylines with villains as the main characters. He'll even figure on the side of the good guys in response to world-spanning alien threats like Brainiac or Darkseid. And if it turns out Lex Luthor comes out ahead after helping to save the world, who can really blame him?
He's got his eyes on the prize.