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