Viking: Battle for Asgard/Galcliff

You'll begin this island on the coast, as your fellow warriors have sailed from Niflberg to help retake the island from Hel's forces.

Distillery
Enter from the SW side, avoid the patrols. Clear the few guards near the captives then free them.

Holdenfort
Go out of the cave and in front of you will be Holdenfort. Go straight ahead to the wall; there are three entrances: one on the left side through the main gate, one in the middle via a low portion of the wall, and on on the far right at the broken portion of the wall.

Don't go around the corner as there will be a guard but right in front of you will be a slit cut out of the wall. Jump over that and wait until the demon has dragged the dead body away. After he has done that go to the left and then straight forward. There will be a group of legion soldiers and a legion champion; after you have killed them go across the bridge there will be archers.

Kill the archer and keep going across the bridge. At the other side there will be more legion soldiers and another legion champion. Slay them, then ignore the additional legion soldiers to your right. Leave them alone unless they notice you.

Go over the walls until you get to a hill. Climb up the hill where there will be even more legion soldiers. Kill them and keep going up to where an archer will come down hide behind the crates. You can either silently kill him or avoid him by hiding behind the boxes and rotating around them in the opposite direction.

Continue to the top of the hill and there will be a portal on your left and some Legion Warriors in front of you. Head forward and slaughter the legion soldiers and grunts (Note: the portal will bring back more legion soldiers, but not grunts). After you have killed the main lot of grunts, go out of the gates and go to your right there will be a place to plant the explosives. Throw them down one of the holes, and it will blow up the barracks.

You'll now be able to initiate the final assault on Holdenfort.

Longship Graveyard
From Holdenfort, head out the north gates by Shaman Asta. Head forward into the cave to kill the legion forces and get some easy gold, then climb up the terraced mountain steps and make your way into the graveyard. As you get to the top you'll see viking warriors peaking around corners, watching you. There will be no enemies here - when you get to the top you'll reach a trap door. A cutscene will take place in which the leader of the guerrilla warriors will tell Skarin that they will not join his forces until he retrieves the dragon gem Hugin from Caldberg.

A new objective will appear on your map on the west side of Caldberg, and like with Darkwater and Holdenfort, you'll have to sneak (or slaughter) your way to retrieve it.