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