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