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