Thanks guys - centaur invasion huh ? Maybe theres a Centaur / Lizard man feud ?

The reason for the lowlands being the dangerous bis was mentioned in post #3. I figured that the whole geography was of marshy lowlands and bogs and that travel over these regions would be difficult so thats probably where the monsters might be so the people were forced onto the higher ground. The whole region is quite dangerous and theres a whole line of forts and armed places to keep the trading route open. My region seems to be a crossing point to get to and from other tiles. It does not seem like a nice pleasant area. I'll comment more later but I am bit pushed for time right now.