Here is the full list of all 55 The Banner Saga 2 achievements.
Defeat 3 enemies with a Berserk.
Visit the godstone Aselei.
Defeat 3 enemies with a Poet.
Import Save Game from Banner Saga 1.
Acquire 3 rank 10 items.
Reach Arberrang in 100 days or less.
With 6 Rank 10 units, win a Hard difficulty sparring battle in the Training Tent.
Fight 32 battles in a single playthrough.
Prevail with Rook against overwhelming numbers.
Kill 5 in one turn with Cull the Weak.
Kill 5 enemies while stealthed.
Maintain an alliance with Rugga.
Complete Sven's Training.
Complete Holfi's Training.
Break 30 barricades in a single playthrough.
Defeat 3 enemies with a Shieldmaiden.
Defeat 3 enemies with a Female Horseborn Cantref.
Defeat 3 enemies with a Male Horseborn Teulu.
Defeat 3 enemies with an Axe Thrower.
Defeat 3 enemies with a Wanderer.
Defeat 3 enemies with Zefr.
Defeat 3 enemies with a Slaughterer.
Defeat 3 enemies with a Tracker.
Defeat 3 enemies with War Bear.
Complete the game on Normal difficulty.
Complete the game on Hard difficulty.
Complete the game on Hard difficulty level without losing a single battle.
Complete the game without letting anyone in your caravan die to hunger.
Complete the game without ever getting low morale.
Meet King Meinolf with Rook.
Meet King Meinolf with Alette.
Visit the godstone Irynx.
Visit the godstone Baldringr.
Visit the godstone Vez'nan.
Visit the godstone Geirraðr.
Visit the godstone Bygglaerer.
Visit the godstone Lauga.
Bring 400 clansmen safely into Arberrang.
Build an army of over 600 trained fighters.
Witness Eyeless possess 10 fallen units.
Reach Oldford with at least 20 Varl following Bolverk.
Bolverk always acts as the Ravens expect.
Kill a Sundr.
Survive with only female Heroes. (Normal or Hard Difficulty)
Survive with only human Heroes. (Normal or Hard Difficulty)
Survive using only parties of 4 varl in every battle. (Normal or Hard Difficulty)
Survive all battles on Easy.
Survive with fewer than 20 Heroes dying. (Normal or Hard Difficulty)
Survive all battles on Hard.
Survive without a single Hero dying. (Normal or Hard Difficulty)
Survive without using the Horn for willpower. (Normal or Hard Difficulty)
Survive without Recruiting Heroes. (Normal or Hard Difficulty)
Survive Hard Mode without a single reload
Survive all battles on Normal.
Survive in less than 180 minutes for your total turns. (Normal or Hard Difficulty)