Redrobes thanx for the info.

Don't worry it will not become peaceful elven meadows, the fens and swamps will remain a deadly place, considering it will also contain Chedalbur undead troops along with the lizardmen, and other swamp nasties. The new race will have an influence over the lizardmen if they in the mood to do so as they sort of related to the lizardmen, but most of the time care less what the lizardmen do providing they don't interfere with citizens of Chedalbur.

Chedalburians (native citizens of Chedalbur) are very hardy race, born out of the cold swamps, evolving into a powerful magical flying race. They enjoy their swamps and live in harmony with them, guarding them ruthlessly mostly with the aid of undead troops they created from the fallen. Magic abilities are generally life & death, cold, weather & nature based. Spell casters tend to be druid/sorcerers. They seldom involve themselves in politics of the outside world, but do keep an eye on their neighbour, always ready to defend against an invasion. Trading with other kingdoms is kept to the edge of the kingdom.

So in annexing the land mass with the swamps, with Chedalbur border cutting through the swamps and fens itself. Mullion town/village would be a safe trading post between the kingdom and Thrublanders within Chedalbur. Hawker Point could be safe haven resting place for those travelling from the west on their way to Mullion.

I thinking of putting a huge underground river travelling under Still Lake connecting the lake with the sea as it is the narrowest land mass. The water level never changes as the lake is connected to the river below.