Your tribe, known as the Fjalts, have been living peacefully side by side with Martek until his ambitions grew over his head. Your tributes were no longer satisfactory, but your land was. The easiest way to conquer your town and tribe was to flood the river, breaking the dams that withheld the water from the sea - washing away the filth - and those who survived became slaves of Martek's empire. Eventually the land would become suitable for growing farms and crops, but not until a man, once a captured slave, took it upon himself to revolt against Martek's insanity. His name was Corlis.
This was designed purely with Definitive Edition's (buggy) editor. For those who like B & D with a few puzzle elements, enjoy this little scenario.