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