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