The River Guard was a military order of Sargos in Aels during the Middle Human Age and the Second Dark Age, founded by Martin the Conqueror, to defend the western bank of the Osorio river against the depredations of the Kanov tribes of El Yermo, and as well to protect the Tardonic March, both against the Kanov and the Tardonic.
Using a combination of fortifications, a fluvial armada and cavalry forces, they will be very successful protecting the human northwest from the eastern invaders from El Yermo, until the Sargonic wars, when they were attacked both by Tardos to the west and in east, by Goblins, Orcs, Gorbegean Kanovs and Enkel forces attacking from El Yermo. The River Guard was afterward dissolved -along with the Tardic March- as these territories returned to the Kingdom of Tardos, but soon afterwards, as the demons returned in the Second Dark Age, the order was reinstated, but now having a much more "international" sense, with a goal to defend not only Sargos, but the Five Kingdoms of the Northwest of Aels.
While terribly outmatched, they will be successful in delaying the advance of the southern columns of the Dark Legion during the Sargonic Campaign in the Second War of the Power in the year 2440 a.a.H.
While originally the River Guard was distinctively a Human organization, being in the frontier of the five human kingdoms of the northwest, they began to accept and incorporate into their ranks non-humans, especially kanov mercenaries of El Yermo and Grey elfs, that served them as magicians and rangers.
While the Order of Nortender was regarded in north Aels as expert monster-hunters, the River Guard will have a similar -but less impressive- fame in the Five Kingdoms.
The River Guard will later progressively decline in the Holy Sargonic Empire, as the border was moved to the east bank, and some Kanov realms as the Christianized Gorbegeos, former enemies of the River Guard, entered the Empire.