Here is the full list of all 39 Vikings - there are Wolves of Midgard achievements.
Unlock all Gifts in Skathi's gift tree.
Unlock all Gifts in Tyr's gift tree.
Complete Campaign 3.
Complete the game as the Shieldmaiden.
All Hunt maps complete.
Found all Legendary Items.
Complete all Challenges on all maps.
Unlock level 4 of the Shipmaster.
Unlock level 5 of the Smithy.
Collect one of every rune.
Complete all Trials.
Become chieftain of all the clans.
Unlock all Gifts in Loki's gift tree.
Complete Campaign 2.
Burn the Imperial Fleet.
Rage continuously for over 20 seconds.
Complete the Imp Hunt.
Equip three runes on a single item.
Earn 50,000 gold by selling resources.
Earn 1,000,000 Blood.
Unlock all Gifts in Thor's gift tree.
Liberate Flotnar village.
Complete Campaign 1.
Keep Draupnir for yourself.
Travel to Utgard.
Survive the Mire-Witch's spell.
Kill 100 Jotun.
Kill four foes in a single attack.
Perform 1000 rolls.
Killed 500 Tomte.
Complete any Hunt map.
Defeat the Jokul.
Defend Ulfung Village.
Complete the game as the Warrior.
Complete Game+.
Complete the game on the highest difficulty.
Unlock all Gifts in Odin's gift tree.
Accomplish campaign in Valhalla Mode
Accomplish campaign in Valhalla Mode on highest difficulty.