Here is the full list of all 12 Spooky Heroes achievements.
Destroy your first rift
You got your first kill. Congratulations !
Kill your first boss
Store 1000 gold in the bank
Unlock the ninth hero
Finish the game
Unlock the priest
Slay 100 enemies
Complete 10 quests
Hatch a dragon egg
Buy and equip a full plate armor
Eat 10 pieces of any food