Castrum is a mysterious bastion-nation of warforged who once hid in the Mournlands, who built a great wall of iron while fleeing sudden exposure after the Dead Grey Mists receded. Next to nothing is known about it, as it is highly secretive.
After the Day of Mourning that ended the Last War, the once-great nation of Cyre was covered in a life-draining fog called the “Dead Grey Mist,” and came to be called the Mournland. During this time, it was uninhabitable, and only the toughest or most foolhardy adventurers dared to explore it.
Eventually, though, a group of scholars, priests, and mages from Xen’drik of all places arrived in the ruined capital of Metrol. Calling themselves the Excavators of the Mournland, they discovered how to create a hybrid work of artificery and alchemy called a “clearstone” that could clear the Mist in a small area. This was used by the Eclipse Collective to found the Kingdom of Eros, but it limited their expansion. The clearstones required time and effort to place, and a wealth of resources to create even one.
Eros frequently came into conflict with the warforged dwelling in the Mists on their southern border. The warforged, immune to the effects of the Mournland, had come to see it as home. The Godforged, a religious sect that was the greatest of the warforged near Eros’ borders, frequently removed clearstones and attacked explorers when they came near. When the Dead Grey Mist cleared at the end of the March of the Damned, however, everything changed.
The Godforged, suddenly exposed, attempted an attack on Eros immediately, as the entire army had been relocated. They occupied Grey Titan’s Hold for a short time before they were forced south by the Eran military, bolstered by the immortal Hammer of St. Derli. They regrouped in the south with other warforged already there and, with surprising speed, set up a great wall of iron, four stories high, spread around all they could reasonably hold.
The Iron Wall of Castrum is broken in three places, where Orien trade roads pass through. Here, heavily-fortified border forts stand, letting nobody through except under very specific circumstances.
Culture & Society
Next to nothing is known about Castrum by outsiders, as it welcomes only warforged, and has not been known to let anybody out. The border guards reveal little, and the few people who have traveled through have commented that it seems “empty” and “eerily quiet.” Its society, if one even exists, is completely undefined.