Býrian River Misprint?
Reading over the Byria module I found a possible misprint on page 3 of Býrian Peninsula under history. It reads as follows: "Târgan Empire began raiding the peninsula for slaves. During the Third Century BT the Târgan armies invaded repeatedly from the southeast, penetrating as far as the Daríana River."
Now I went looking for the river on the Byria map and only found the Daríama river and cross-referenced it with the Tuvara map which it extends in to. Also as the Daríama river.