Now Maharshinaga, called Nago, general of the imperial forces, had not been idle over the years. He knew the plains tribes would return to this valley in one more year, or twelve years after that. One generation or ten, they would follow the nutrients downriver with the herds and the plantlife and the birds and the turtles. They would follow the food. He had ambushes and mantraps laid throughout the valleys and a teaming civilisation of disgruntled hunters and captured wives spread through this confluence of three continents, all of whom deferred to him with religious awe.
He certainly wasn't planning to return to the empire. And a good many middle aged 'lost boys' with captured and not-so-captured middle-aged wives were of the same mind. There were always the career officers and the religious zealots coming through the ranks, though. The older fighters tended to send those ones to the frontier and usually the former more than the latter, so the army was loyal to him as much as to the old land. Nago's wife was fat, toothless and extremely flatulent, and he loved her dearly, not to mention all the other wives. There were always a few dozen children and servants underfoot these days, as well, running around and running the castle respectively.
Oh yes, the castle. It was a cunning collection of cross-beams and sculped river-clay, based loosely on an ancient technique called the Termite Mound which could house entire tribes against large predators, except in this case it was shaped by Nago's unlimited resources and deeply ingrained delusions of grandeur. Inside it was what we might call a cosy, four-bedroom townhouse in the mediterranean style but with added nooks and crannies and unexpected staircases, but from the outside it appeared to be a giant serpent, coiled and poised to strike, thirty feet in the air. When Nago's beloved, plump wife made tea, the window-eyes of the snake glowed red, and smoke hissed from it's open maw.
The new recruits were always suitably impressed, of course, to say nothing of the natives. Many went mad with terror, it really was very amusing. . As a matter of hygeine, there was a moat of perpetual fire, fueled by whale oil, and a crocodile pit under the trapdoor in front of the dais on the ground floor. Nago sits there most days, from eleven to five or so, with his best python-skull hat and snakeskin cape, holding court. At the gate of the castle is a sign which reads, in the ancient tongue of the plateau empire, "The Witchdoctor Is In."