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