Location
The Iron Authority is located on the Beynsfal Plateaus, south of the Rifenmist Jungle on the Rifenmist Peninsula. The core of the Iron Authority consists of five major city-states who all swear fealty to the Iron Emperor in Tz'Arrm, the capital and southernmost city on the plateau:
Tz'Arrm, the capital of the empire.
Rybad-Kol, city of the Forge Lords
Hdar-Fye, the necropolis of Prince Hdar
Ezordam-Haar, eyrie of the red pegasi
Ortem-Vellak, the petrified elventree
History
It was on what is now the Beynsfal Plateaus that one of the last battles of the Calamity took place. History records that here Bane, the Strife Emperor and his armies of goblinoid legions fought against the Wildmother and her Free Children and lost. (This history doesn't mention that the Wildmother was not the only one of the Prime Deities who ambushed the Strife Emperor there, west of Rybad-Kol.) When the Strife Emperor was defeated and banished to his planar prison, his iron armor remained and fell to the ground. The helm is used as the palace of the Iron Emperor, while the rest of the armor is used to supply the war machine of the Iron Authority.
After the Calamity, the hobgoblins asserted authority over the different goblin tribes, and the various hobgoblin kingdoms of the plateau launched military campaigns against each other. For most of the Era of Reclamation, no hobgoblin tribe dominated for long until they fell to internal distrust and greed.
However, around 722 PD, the Iron Authority emerged and conquered the plateau, but their empire did not fall. With the whole of the Beynsfal Plateaus under the control of the Iron Emperor, Tz'Jarr, the Iron Authority began their long war to subjugate the jungle below. In the decades leading up to 836 PD, the Iron Authority had gone through many cycles of war with the jungle as new warlords rose to power within the empire, launched raids, and eventually ran out of steam.
In early 843 PD, Tetrarch Umejii of the Qoniira Tetrarchy traveled south from Niirdal-Poc to investigate whether the Iron Authority was the "terrible" thing that was intuited to be coming.
Society
The Iron Authority is extremely hierarchical and regimented, with each person knowing their place exactly: whom they serve, and who serves them. At the top of this military dictatorship is the Iron Emperor, ruling from Tz'Arrm. Paying fealty to him are four royal generals who rule the other four city-states of the empire, and an overclass of other generals. Beneath them is a hierarchy of military and intelligence officials, nobles, and their cronies; all are driven to increase their power, which they guard jealously, because one only leaves one's position through promotion or death, and one can only be appointed as a leader by the Iron Emperor or one's immediate superior. Then there are merchants, indentured servants, and other members of the serving class, who rank only above the empire's many slaves. This structure is promoted by constant, stirring propaganda and enforced by numerous secret police. The Emperor's son is his heir, and has been groomed to be a great general.
The entire population is pressed into compulsory military service. The power-hungry clerics of the Strife Emperor bestow the Curse of Strife on the empire's troops, allowing that god of bloody conquest and tyranny to whisper in the soldiers' minds, amplifying their aggression in various useful but unpredictable ways.
Hobgoblins make up the majority of the empire, and as the Iron Emperor has declared the racial supremacy of hobgoblins, they fill almost the entirety of the upper ranks of society. In the imperial capital of Tz'Arrm, 70 percent of the population are hobgoblins. Another one-tenth of the population are goblins living as second-class servants. The remaining one-fifth of the population are other races captured as slaves in the Authority's wars of conquest; the slaves are generally laborers used to chip iron scraps from Bane's fallen armor or to forage for food in the jungle, since the Beynsfal Plateau has been devoid of plant life since the cataclysmic battle that felled Bane. While tieflings are valued as slaves for their ability to handle the heat (including work in the furnaces), elves are highly desired for their beauty, long life, and the difficulty of acquiring them in the hostile jungle. Goblins and bugbears are commonly slaves themselves, though they rank above non-goblinkin.
By 812 PD many hobgoblin warbands that threatened the hillfolk of Tal'Dorei owed their allegiance to the Iron Authority, but these field scouts' separation from the Authority's propaganda gave more rein to individual goals.
As late as 836 PD the other powers of the continent knew little about the Iron Authority aside from rumor; the vast, hostile jungle and the Iron Authority's forces generally kept explorers from learning much or even filling in maps, though cartographer Tyriok Gadsworth had seemingly managed the feat by 812 PD. The Orroyen tribes and Mornset Countryside feared the Iron Authority but were torn about the prospect of the Republic of Tal'Dorei someday sending armed forces to the region; meanwhile, the Republic's Master of Defense, Tofor Brotoras, was wary of provoking the war machine. Some of the Orroyen elves had fled north to Syngorn as refugees, while an ambitious few had willingly joined the Authority. A fair number of hobgoblins had escaped the Iron Authority to cities like Byroden, Kymal, and Emon, with their stories of life in the empire.