Full list of all 101 Skul: The Hero Slayer achievements.
The base game contains 57 achievements, and there are 5 DLC packs containing 44 achievements.
Restore the Demon King Castle to its original form
Acquire Master Ninja
Acquire Poseidon
Acquire Royal Guard Captain
Acquire Dark Avenger
Acquire Nightmare
Acquire Warlord
Stay in the black market for 5 minutes
Acquire Elder Ent Skull
Defeat the First Hero as Little Bone
Defeat the First Hero without saving the stage NPC
Keep talking to Headless
Acquire Super Rock Star
Acquire Gold Gargoyle
Play on Rookie Mode
Defeat the First Hero without getting hit
Defeat St. Joan II without getting hit
Acquire Sniper
Defeat the Leiana Sisters without getting hit
Acquire Joker
Acquire Minotaurus III
Acquire Devil Berserker
Acquire Vanguard Captain
Defeat Chimaera without getting hit
Acquire Defender Captain
Acquire Soul Knight
Acquire Carleon Commander
Acquire Magnifico
Acquire Ghoooooul
Reach the top of the chandelier in the Demon King Castle
Acquire Dark Alchemist
Acquire Frozen Spirit
Acquire Neo Samurai
Acquire Demolitions Expert
Rescue the Demon King and return to the Demon King Castle
Defeat the Sword of Carleon, the First Hero
Acquire Eternal Mummy
Defeat the archbishop of the Leonia Order, St. Joan II
Acquire Eternal Werewolf
Keep restocking from the collector
Acquire Gambler
Acquire Abyssal Monarch
Kill 100 adventurers
Acquire Arch Lich
Defeat the distorted goddess, Chimaera
Acquire Destroyer
Acquire Desperado
Defeat Yggdrasil without getting hit
Acquire Grim Reaper
Acquire Yaksha
Acquire Champion
Defeat the adjutants of the Gold Mane Knights, the Leiana Sisters
Defeat the elder ent, Yggdrasil
Die from a trap
Return after experiencing death
Stay in the black market for 1 minute
Reach the top of the throne in the Demon King Castle