A kingdom forged during the Age of Destiny by a necromancer of incredible power and insidious vision, Geb is now renowned as a land of the undead, and while plantations filled with zombie labourers may stick in the mind, there is much, much more to Geb.
During the zenith of Osirion, the land that would become Geb was the southernmost part of its territory. As Osirion's power declined, the pharaohs ceded control of the land to the the exiled Osiriani necromancer Geb in -929 AR.213
War with Nex
Until the coming of the archmage Nex, Geb was a reasonably peaceful nation. In -892 Ar, Nex's expansion southward into Geb ignited the most infamous magical rivalry in Golarion's history as Geb plunged the land into war with neighbouring Nex(named in honour of the nation's archmage ruler). During one of the most deadly exchange of spell power, the necromancer Geb sucked the life from most of the land surrounding the cities of neighbouring Nex by the use of wishes. In return, Nex blighted the lands of Geb with a series of cataclysms that decimated the population. Geb responded by animating casualties into legions of the walking dead, beginning Geb's reliance on undead.1
After another vicious attack in 576 AR, Nex vanished into the Refuge of Nex; to date no trace has been found of him. Geb knew that Nex was still alive, and was distraught that he did not get to vanquish his centuries-old rival. After several decades living in resentment, his torment grew unbearable and he committed ritual suicide in 632 AR. However, it was to no avail, as Geb's rage, disappointment, and necromantic connections led to him returning as a ghost and dooming him to continue an undead existence until he can be sure of his old rival's fate.14
Land of the Undead
With its ruler now an immortal ghost, and much of the populace animated as skeletons and zombies, the land of Geb became known as a land of undead, much to the dismay of neighbouring and not-so-neighbouring nations. The land was forced to fight off countless raids and naval attacks.
The raid with the most long-lasting implications was carried out by the Knights of Ozem, seeking to add to their glory following the conclusion of the Shining Crusade. Their attack failed, and Geb was so incensed that people from so far away would choose to launch an unprovoked attack on his kingdom, that he animated six of the fallen knights as graveknights. He ordered his new undead minions to travel to Lastwall(now The Gravelands) in order to retrieve the corpse of Arazni, the revered former herald of the god Aroden as well as the Knights' patroness. They were successful, and Geb took a year and a day to drag Arazni's soul back from the Great Beyond. Over a period of years, Geb corrupted her into a lich with none of her former personality. Geb made Arazni into his trophy wife and forced her to rule his nation in his name, something which he saw as beneath him.56
In 4719 AR, after Arazni escaped from Geb's clutches while Geb himself became convinced of Nex's imminent return, he returned to active rulership of his kingdom.