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