As one of DC Comics’ greatest rivalries, Superman and Lex Luthor have quite a storied history, and it reached its satisfying conclusion in Grant Morrison and Frank Quitely’s All-Star Superman. While most fans would expect the two characters’ feud to end in a climactic final battle, the story portrayed the Man of Steel’s greatest victory when Lex Luthor did the unthinkable. After decades at the alien’s throat, he finally saw that Superman is right about everything.
An Elseworlds story detailing Superman’s last days, All-Star Superman introduced fans to a Clark Kent who was simultaneously more powerful and more mortal than he’d ever been before. But he wasn’t the only one who got a power boost. When Lex imbued himself with powers befitting the Last Son of Krypton, he finally saw the world through Superman’s eyes.
All-Star Superman #12 by Morrison and Quietly brings Lex and Kal-El's decades-long feud to a close as a dying and depowered Superman goes head-to-head with a superhuman Lex Luthor. Using a formula of his own creation, Lex has all the abilities of Superman without the moral compass for twenty-four hours. Using a gravity gun to speed up Lex’s internal clock, Superman plays possum just long enough for Lex’s heightened senses to kick in. Overwhelmed by his new perception, and understanding the connectedness of all living things, Lex says, "This is how he sees all the time. Every day. Like it’s all just us, in here, together. And we’re all we’ve got," as his new powers begin to fade. Now human once more, Lex rushes Superman, blaming the Kryptonian for taking away the insight that would have allowed him to save the world. Clark responds with a hard right cross and the line, "You could have saved the world years ago if it mattered to you, Luthor."
In typical Luthor fashion, Lex manages to turn his failings around on Superman, but by then the damage to his ego is already done. For one brief moment, Lex saw the world the way Superman does, and he came to the exact same conclusions. A character as greedy and selfish as Luthor can’t exist in a world so connected, and the way he blames that same selfishness on his alien foe is all the proof that readers and even Luthor himself need to see the truth. In a world dependent on selflessness, he's the real alien.
More than any other hero, Superman understands the importance of what he does. The impact of his actions is entirely visible, if only to him. And while other villains like Darkseid or even the Joker may be more inherently evil than Lex, more than any other villain, Luthor truly believes he’s the hero of the story. Superman is the ultimate hero and Lex is the ultimate villain because they represent the clash of altruism against self-interest. Superman has often doubted himself in the comics, wondering if he's doing too little to help improve the world, or so much that he's enforcing his own views on humankind, so while he's thwarted Darkseid and punched out Doomsday, having Lex Luthor walk a mile in his shoes and come to the same conclusions is his true greatest victory.