|WARNING! This article contains MAJOR spoilers for the recently released novel To Brave the Storm. Caution is advised.|
The culture was a race of humanoid natives who had curious skin coloring, divided perfectly along the middle: some were black on the left side and white on the right, others were white on the left side and black on the right. Two sides were deeply divided, with those black on the right side oppressing those white on the right side. Several millennia ago, both sides completely wiped each other out in a series of wars based on mutual racial hatred. There were only two survivors, one of each side: Chief Officer of the Commission on Political Traitors Bele of the black-right; and Lokai, a revolutionary of the white-right. Bele pursued Lokai across the galaxy millennia to come (TOS episode: "Let That Be Your Last Battlefield").
Cheron was also located in a strategic position relative to the planet Vulcan. Some time before the 22nd century, the Romulan government occupied the planet and began to use it to spy on their ancient cousins. (ENT novel: Kobayashi Maru)
In 2160, Admiral Valdore massed his forces at Cheron in preparation for an all out attack on Earth. Tucker was able to inform T'Pol of this build up via their shared mind link and T'Pol informed Captain Archer. Archer then convinced the Earth Starfleet to mobilize forces to Cheron. These forces then engaged Valdore's in the decisive battle of the war. (ENT - The Romulan War novel: To Brave the Storm) The battle a humiliating defeat for the Romulan government. (TNG episode: "The Defector")
In 2268, after 50,000 years of pursuit, Bele and Lokai came aboard the USS Enterprise and finally returned to Cheron to find it destroyed. They beamed down and continued the hunt forever (TOS episode: "Let That Be Your Last Battlefield").
What they didn't know But they went underground,, and there were 30 more of them,,,, on cheron