if you killed the giant tree he drops a crypt key for the swamps , yes swamps should be done before mountain , the swamp boss drops something for you to use in the mountain the mace is your best weapon there btw , a bronze sword does also work in the swamp , if you have a boat you can kill serpents in the ocean - you get iron from the crypts in the swamp and a long boat is made from swamp stuff - iron and ancient wood you get in the swamp ....best way to hunt serpents with a bow from the long boat....serpent shield is made from iron and serpent scales , the scales drop to the bottom of water so lead a serpent to shore and you can get the scales , also the best early food is made from their meat