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