After the primordials were defeated in the Dawn War, there was a effort made by the Covenant to send the chaos archons back to Chaos. Some of them were hidden so well that they escaped the search. The largest of these hidden armies was sequestered on Osâchar. Those of this world were descendants of chaos archons that once served under the primordial Sarseg. In the Dawn War, there were three groups that served him, all mercenary types, born into service, or malcontents from other primordial armies. Sarseg had the archons use their water, earth and air magic to create a vast underground complex called Balsyn. Sarseg made sure that once the chaos archons went in, they could not get out. He did this because he did not want the size of his army to get out to the other primordial generals. His secret army was to be used if the primordials were victorious in the Dawn War, protecting his claim over Osâchar. In the final years of the Dawn War, Sarseg was ordered to go to Bal-Kriav and battle the gods and angels. He took his surface army, but left his secret army hidden deep within Osâchar. When Sarseg perished in Bal-Kriav's Web of Magic, his secret army was left forgotten. His army labored away in the depths for thousands of years, following the last orders of their master to continue building a massive underground city-sized stronghold.
Sarseg's Hydrocur were the first group of chaos archons to gain their freedom from Balsyn. They were discovered by Durkoth following Sarseg's ancient encrypted texts. These Codices of Sarseg took nearly five centuries to decipher. Once deciphered, they showed the way into Balsyn, past nearly twenty miles of trap-strewn passages and guarded vaults. The vaults act as teleportation devices with encrypted passages that are unlocked with the cipher keys found in the Codices of Sarseg. It took five years for the Durkoth to make it to the water sector of Balsyn. In this area they found the Hydrocur. These creatures were still loyal to Sarseg, yet changed allegiance when the Durkoth read Sarseg's codices, releasing them from allegiance to their long-dead master. When the the Spire of Molakh-Búle came to Bal-Kriav, it had aboard an army of Hydrocur in service to the Durkoth.