Here is the full list of all 12 Darkest Hunters achievements.
Unlock your first new character.
Find your first secret.
Defeat your first boss.
Upgrade any of your items to level 3.
Start mission number 1.
Collect all notes.
Play in Multiplayer mode.
Open 100 chests.
Unlock all available spells.
Collect and equip all elements of one set.
Kill the Furious Lord of Darkness.
Collect all stars.