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