Full list of all 53 Fell Seal: Arbiter's Mark achievements.
The base game contains 43 achievements, and there is 1 DLC pack containing 10 achievements.
Defeat at least 4 enemies with a single hit
Defeat Morgaine
Complete the Obelisk riddle
Complete the Ancient Path
Cleanse the Cursed Shield
Win the second Tournament
Craft a final-tier weapon
Visit the fifth Relic
Defeat an enemy with a Berserk, Charmed, or Mind-Controlled enemy
Master all 6 special badge Classes
Master all Human story character Classes
Complete the Halloween encounter
Recruit Kairu
Obtain all gadgets
Visit the fourth Relic
Master all 20 base Human Classes
Open 50% of treasure chests
Unlock the Spymaster Class
View all optional dialogue events
Defeat Lady Anquine
Use your first Class badge
Recruit Katja
Save Somier a second time
Drown an enemy
Visit the third Relic
Recruit Bzaro
Unlock all 20 base Human Classes
Win the first Tournament
Visit the second Relic
Master any Class
Unlock the Demon Knight Class
Recruit Yates
Visit the first Relic
Defeat an enemy by using a Counter Ability or Thorns
Unlock the Marked Class
Defeat an enemy with falling damage
Craft your first item
Change Class at least once
Defeat a unit with its Elemental weakness
Get the first ending
Get the second ending
Open all treasure chests
Master all 19 base Monster Classes
Master all 22 Monster Variants.
Complete all unique Hunts and large-scale battles.
Complete all Missions.
Master the 3 new Human Classes.
Defeat an enemy with a Pet Effect.
Complete an encounter deploying only Monsters.
Fully upgrade all 5 regions.
Complete 100% of Missions in one region.
Build a Guild Upgrade.
Enlist each of the base 18 recruitable Monster types.