Here is the full list of all 99 Mushi achievements.
The base game contains 0 achievements, and there is 1 DLC pack containing 99 achievements.
Level up a warrior to level 20
Level up a rogue to level 20
Level up a mystic to level 20
Equip your first ring
Discover all areas in the world
Reach crafting level 200
The giant rabbit in the glade
The big boar
The cursed plant in the forest
The huge claw on the coast
The crusher of shells
The bandit in the hills
The bandit leader in the hills
The creature in the swamps
The witch in the swamps
The king in the jungle
The turtle in the desert
The hornet in the desert
The golem in the northlands
The gnome in the northlands
The creature in the northlands
The reaper of the night
The fallen knight in the woods
The undead champion at the plains
The molten beast at the plains
The lava golem at the plains
Discover area in the world
Complete the dungeon Shimmering depths
Complete the dungeon Deep mines
Complete the dungeon Cursed temple
Complete the dungeon Ant nest
Complete the dungeon Wizard tower
Complete the dungeon Molten forge
The skalidra king
The dwarf warlord
The ancient siren witch
The queen of the swarm
The master of the tower
The overseer of the forge
Equip a ring in each slot
Use magic scroll to enchant ring
Use a magic scroll to enchant ring
Use magic scroll to enchant weapon
Reach A-grade on any character
Reach level 30 with any class
Reach level 40 with any class
Reach level 50 with any class
Reach level 60 with any class
Reach level 70 with any class
Reach level 80 with any class
Reach level 90 with any class
Reach level 100 with any class
Reach max level with all classes
Reach max level with Tyrant
Reach max level with Blademaster
Reach max level with Paladin
Reach max level with Phantom
Reach max level with Ravager
Reach max level with Stalker
Reach max level with Archmage
Reach max level with Bishop
Reach max level with Soultaker
Reach max level with Beastmaster
Reach max level with Warlord
Reach max level with Lich
Ascend once with any class
Ascend 5 times with any class
Ascend 10 times with any class
Reach max level on any class with no deaths
Reach max level on a warrior class without dying once
Reach max level on a rogue class without dying once
Reach max level on a mystic class without dying once
Level up all warrior classes
Level up all rogue classes
Level up all mystic classes
Defeat dungeon boss
Collect all pets in the game
Unlock all achievements