The Missions and Monsters Add-on for Fell Seal: Arbiter's Mark has 10 achievements.
Build a Guild Upgrade.
Fully upgrade all 5 regions.
Complete 100% of Missions in one region.
Complete all Missions.
Master the 3 new Human Classes.
Enlist each of the base 18 recruitable Monster types.
Complete all unique Hunts and large-scale battles.
Master all 22 Monster Variants.
Defeat an enemy with a Pet Effect.
Complete an encounter deploying only Monsters.