A far-distant, desert-like world, revolving about the red star X-156-99F, whose people were the custodians of a great scientific civilization until their culture retrogressed to barbarism. Named in honor of Lex Luthor, Superman's arch-enemy, it is the one world in the universe where Luthor is considered a hero, while Superman is feared and detested as a super-villain.
Since the gravity of Lexor is considerably heavier than that of Earth, an earthman on Lexor must wear special "gravity shoes" merely to move about. The planet's catastrophic water shortage is alleviated by Superman in October, 1963, but Lexor remains a barren, hostile, drought-stricken world, swept by mighty sand-storms, its sun-parched landscape dominated by a weird cactus forest, its skies filled with monstrous birds called "dorulgs" which prey on the Lexorians' meager crops.
Another of Lexor's topographical features is its weird jungle, home of the "truth beast," a bizarre creature whose strange powerful brainwaves make anyone close to it tell only the truth, and the "madness flower," whose baleful perfume induces temporary insanity. In addition, strange beasts with big hollow horns have evolved on the planet, traveling long distances in search of scarce water and then carrying it about with them in their oversized horns. Lexor's famous Living Lake, seemingly a harmless small body of water, is actually a giant jelly-fish form of Lexorian life capable of devouring anyone foolhardy enough to venture into it. Moreover, because Lexor revolves about a red sun, Superman has no super-powers there.
Although present-day Lexorians are unscientific, they were, in ancient times, a great scientific race who had developed and mastered an extraordinary super-science, evidence of which may still be found inside the museum of old machines in Lexor's capital city.
Among the miraculous relics of Lexor's forgotten science on display in the museum are a lesson machine, with which both Luthor and Superman teach themselves the Lexorian language within the space of a few hours; automatic building machines, which can be programmed to construct other machines; an automaton bloodhound, originally designed by Lexor's ancient scientists for trailing law-breakers; an inventing machine, for creating new inventions and devices; and an artificial super-powers device, designed to give a human body a temporary charge of super-powers.
Sometime in the distant past, however, the Lexorians lost the ancient wisdom of their forefathers, and, with it, the knowledge of how to use and operate their forefathers' ancient inventions. Visiting Lexor for the first time in October 1963, Luthor speculates that "This must have once been a great scientific race, but perhaps a great war eons ago wiped out their civilization and they've returned to the Stone Age!"
Six months later, however, in April 1964, Superman discovers that the real explanation for the decline of Lexorian civilization lies in the baleful effects of certain priceless rainbow crystals, a geological rarity whose magnificent rays have, for generations, been used as the source of light in every Lexorian home. Unknown to the Lexorians, however, these same crystals, which Lexorians prize as the greatest treasures of Lexor, emit a subtle vibration that deteriorates brain-activity, a vibration capable, given centuries of exposure, of reducing an entire people to a primitive state.
As explained in Superman #168, "The People of Lexor once had a brilliant civilization but declined to barbarism! The rainbow crystals are the reason - the subtle rays of these crystals act to slow the brain's electroencephalic action, and dull the intelligence!"
Shortly after having made this discovery, Superman destroys the crystals thereby arresting the process that, for centuries, has been dulling all minds on Lexor.
The people of Lexor revere and idolize Lex Luthor as the man who revived the forgotten science of their ancestors and bettered their whole world.
In the words of one Lexorian, "..mighty Lex Luthor discovered the lost science of our ancestors and turned our barren planet into a world of plenty!" So great, in fact, is the Lexorian's love for Luthor, that the mere fact that he is Superman's enemy is sufficient to make them regard Superman as "the greatest villain in the universe."
Indeed, Luthor has made an extensive study of Lexor's ancient super-science and has performed a number of genuinely selfless acts on behalf of its people. Luthor has himself described Lexor as "the one world in the universe I really love," and, within limits, it is fair to regard him as the Lexorians' hero and benefactor.
The principal feat upon which Luthor's reputation with the Lexorians rests, however, that of relieving the planet's calamitous drought by bringing about the construction of vast canals and filling them with vast masses of ice from outer space, was actually performed by Superman, and the fact that Luthor has received credit for this deed is only the result of a monumental misunderstanding on the part of the Lexorian people.
Nevertheless, Luthor continues to be acclaimed on Lexor as the great hero who brought water to the Lexorians' drought-stricken world, and they have named their world Lexor in Luthor's honor. For this reason, and because Superman has no super-powers there, Lexor is a haven for Luthor and a place of deadly danger to Superman.
During his various sojourns on Lexor, Luthor resides in the planet's capital city, in the palace built by a grateful people for their hero. The Lexorians have also provided Luthor with a fully equipped laboratory, where he continues his research into Lexor's ancient science. Elsewhere in the capital is the Luthor Museum, dedicated to the glorification of Luthor and his exploits, as well as a gigantic standing statue of Luthor bearing the inscription:
In honor of Lex Luthor for His Many Scientific Feats Erected by the People of Lexor
The museum housing Lexor's ancient superscientific machines stands not far from the statue.
Luthor's girl friend on the planet Lexor is Ardora, the lovely young Lexorian woman who becomes his wife in November 1964. Other inhabitants of the planet Lexor include Garn Abu, Lar Than, and Vel Quennar.
Clad in a distinctive red-and-purple costume - and employing the name the Defender - Lex Luthor has also functioned as Lexor's super-hero. It should be noted, however, that Luthor's conception of his super-heroic duties consists almost entirely of "defending" the Lexorians against "invading outlaws like Superman." To the people of Lexor, however, Lex Luthor remains the greatest man in Lexor's history, and they would willingly defend him with their lives. (TGSB)