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