The Kerak is an enormous, fortified barrier wall, which was built by the Ravinian Empire between the years 436-530/5.
The Kerak was built for one purpose—to keep the hated Vilzari from invading the southern regions of the Empire. Its construction was a direct result of a series of bloody invasions of those regions of the Empire by the Vilzari, the most recent of which had ended disastrously in 430/5. Upon its completion, the Kerak stretched east from the cliffs of the Sea of Ralas to the western foothills of the Redpeaks Mountains.
The walls of the Kerak stood about thirty-five feet tall, and ten feet wide, and were made of pale grey stones, imported from quarries all across the Empire. The wall measured a little over 322 miles in length and was strengthened with 520 watchtowers and 135 keeps.
The larger keeps were located every two and a half miles along its length. A watchtower was located every half mile. For each large keep, there were four watchtowers. The seventy-foot tall keeps were the main outposts.
The forty-five-foot watchtowers served as defensive strong points and well-stocked garrisons for the small units of soldiers stationed at every one. Each tower had a tall torch pole on its roof that could be quickly lit in warning, if an invader was attacking.
Also spaced every 500 yards along its length, were more than 2,000 single story blockhouses on the wall that served as small strongholds for troops to retreat to in time of need. The Kerak took nearly a century to complete.
Upon its completion, the Imperial Ravinian Army eventually stationed over 60,000 troops along the wall’s length. The single largest and most powerful battlement along the Kerak was Athos-Gelynar, also known as the "Gateway Keep," which served to guard the main entrance along barrier. The main gate was located at the intersection of the Kerak with the Desert Road.
In addition to the Gateway Keep, two other massive fortresses were built at either end of the Kerak; Castle Sandstone at the eastern edge and Castle Greyguard at the western edge.
As a defensive fortification, the Kerak was only moderately successful, in that it never prevented any further Vilzari invasions, instead only slowing them down for a few weeks at a time.
Worse, the Kerak tied down so many Imperial troops that other interior regions of the Empire could not be adequately defended.
After the fall of the Ravinian Empire, the Kerak was completely abandoned and fell into a state of disrepair.
Over the centuries, various rulers of Eldara ordered portions of the wall repaired and strengthened. but these projects were never completed because of their enormity.
Today, the Kingdom of Eldara can afford to station only about 5,000 soldiers along the entire length of the Kerak; more than half of which lies in ruins. More than 500 of its towers and keeps are abandoned.