The forest ratmen were on the loose, overrunning the land and pushing out stout elves, heroic dwarves and berserk trolls wherever they found them. As the ratmen invaded region after region, other factions left this world, but not for long. They only retreated for a little while as they regrouped and then returned with fresh vigour but reduced strength. The battle was on and there wasn't much room for everyone on the map. After all, it was a Smallworld by Days of Wonder.