Korghos Khul is a Mighty Lord of Khorne. He was prominently featured in the Realmgate Wars as an antagonist, and hasn't really been brought up much since, apart from a Black Library novel about his origins.
He was apart of the Khul tribe in Aqshy back in the Age of Myth, and he was called Athol Khul. This tribe did its usual Conan shtick until an unfortunate chain of events happened that caused him to pledge himself to Khorne. These events were caused by Khorne, who also subtly stoked the anger of Khul's tribe over time, showing that Khorne is capable of Tzeentch levels of planning, he just prefers honest bloodshed. It helped that the people of Aqshy were passionate and didn't shy away from a fight.
He then initiated a culling of his tribe, forging the strongest survivors into a Warband called the Goretide. At some point he found a Flesh Hound, called it Gristlemaw and made it his pet. From there, Khul promptly went on to skullfuck a vast amount of Aqshy. He even made a literal pyramid of skulls and was one skull away from becoming a Daemon Prince. It was during this time that Khul first encountered the Stormcast, and while they'd been smashing in Chaos face unchecked, Khul managed to deal them their first defeat, besting Vandus Hammerhand in a fight but failing to kill him. Later, when Khul was literally one skull away from daemonhood, the stormies came and spoiled his fun again, foiling his plans to ascend to a Daemon Prince.