One of the more unusual lifeforms in the universe is Ranx the Sentient City. Its origins are unknown. According to folklore, Ranx is as old as the stars. Circuitry running across and through each quadrant of the city enables Ranx to observe and act upon anything in his vicinity. Ranx can control gravitational forces in virtually any area, and control the very ground itself. Data feeds connect to a command center with a central processing unit, perhaps a quasi-organic brain.
In ancient times, Ranx was located at the crossroads of trade routes located in Space Sector 73. A thriving port, Ranx eventually grew greedy and fed upon the lives within it, growing hungry for more inhabitants. Crime and vice took hold among the population until the city itself became a source of evil.
The Green Lantern Corps had to shut the city down for the good of the sector. When the trade routes diverted, Ranx became no more than a deserted husk. Over the eons, the city drifted into a backwater nebula and was all but forgotten, but Ranx would never forget what the Corps had done. Ranx's only inhabitants became criminals and drifters with nowhere else to go.
In the early 21st century, a member of the religious cult known as the Children of the White Lobe abducted the daughter of a politician from one of the worlds in the Mytonian Cleft. Green Lanterns Chthos-Chthas Chthatis and Guy Gardner tracked the kidnapper to Ranx. His long hatred of the Green Lantern Corps had not abated, and Ranx brought the very ground to rise against the ring wielders in the form of a giant humanoid. When that attack failed, Ranx tried to block their way with gravitational distortions. Finally, the Green Lanterns threatened to disconnect Ranx from his data feeds. Unable to fend them off, Ranx did not prevent them from locating the lobe-spawn.
Though they thwarted the kidnapping, they were unable to capture the lobe-spawn as she detonated herself in a massive blast described like existence itself blinking. The blast caused Ranx traumatic peristalsis which vomited the intruders out of Ranx. Years ago, the Green Lantern Corps had made Ranx lonely. Now, the Green Lantern Corps had humiliated him. For this, Ranx swore revenge.
The resurfacing of Ranx as well as the rise of the Children of the White Lobe was of particular concern to the Guardians of the Universe. Years ago, Abin Sur of Ungara, then-Green Lantern of Space Sector 2814, broke the Guardians' quarantine of Ysmault to rescue the survivors of a crashed Ungaran spaceship. He was offered assistance by the entombed demons known as the Empire of Tears. One of the demons, Qull of the Five Inversions, promised to give the answers to any three questions. The third question, known as the Prophecy of the Darkest Night concerned the final battle of the Green Lantern Corps.
"After untold millennia, the enemies of the Green Lantern Corps will rise united against them.
The Corps shall be destroyed to the last life form. The planet Oa shall be as dust.
Among the gathered foeman shall be numbered
the Weaponers of Qward, Ranx the Sentient City, and the unspeakable Children of the White Lobe.
The Empire of Tears, finally released from entombment, shall join the assault.
Sodam Yat, a Daxamite hailed as the ultimate Green Lantern will perish battling the lobe-spawn.
The planet-form Green Lantern Mogo will be the last to fall as Ranx explodes a blink-bomb within his core."
Ranx was at some point inducted into the Sinestro Corps, though it is not confirmed if he wielded a yellow power ring. His size was increased dramatically, from city to that of a moon. The Sinestro Corps were given room to torture their enemies within Ranx. The Children of the White Lobe united with Ranx and the Sinestro Corps in an attack on the Green Lantern Mogo in Space Sector 2261. By eliminating Mogo, the Green Lantern rings would not be able to locate successors should their wielders be killed.
Ranx wanted revenge upon Guy Gardner and would not strike until promised by Enkafos that he would indeed have his revenge. Using the power of Ranx's gravity disruptors, the Sinestro Corps carved deep inside Mogo to get to the power ring at his core. Ranx believed wrongly that Mogo was hiding Guy Gardner from his wrath. A number of Lobe Spawn travelled through the tunnel carved by Ranx in order to sacrifice their lives to destroy the planet-form Green Lantern. They, in turn, were stalled by members of the Green Lantern Corps.
While most fought on and around Mogo, a small strike force of Green Lanterns was sent against Ranx. The Lanterns discovered that, in his rage, Ranx was overloading his gravity disruptors. This threatened to lose control of the disruptors’ power source, a subspace link to a grade four black hole. The gravitational feedback would destroy everything within a two light year radius.
One of the Green Lanterns that stormed Ranx central command was Chthos-Chthas Chthatis. Ranx recognized the Lantern from their previous encounter, angering him even more. Chthos-Chthas Chthatis was slain by Enkafos, while Green Lantern Stel of Grenda attempted an interface with Ranx central processor. As fast as Stel reduced the power flux, Ranx increased it. Once the Guardians rewrote the Book of Oa to allow the Lanterns to wield lethal force against Sinestro and his allies, Enkafos was cut down by Sodam Yat of Daxam. Yat took over for Stel and told his fellow Lanterns to go, then he destroyed Ranx.
Despite being outnumbered, the Green Lanterns had managed to turn the tide of battle. The Children of the White Lobe were either captured or dead, as were the members of the Sinestro Corps who had not withdrawn. At this time it appears there is nothing left of Ranx, though it is not improbable that he might somehow be restored in the future.