Here is the full list of all 27 Wormskull achievements.
Volkor Joined the team
Reached Shar Vahl
You got your Silver Ring back! How nice.
Used a Phoenix Down III to bring back a grandson.
You killed the powerful Demon Enoch. Great job you hero.
Reached level 2 Alchemy
Reached level 2 Fishing
Reached level 2 Crafting
Reached Level 2 Mining
Reached Level 2 Foraging
Reached level 10 Fishing
Reached level 10 Alchemy
Reached level 10 Crafting
Reached level 10 Mining
Reached level 10 Foraging
Reach level 24 with Duncan
Reach level 24 with Maduin
You found the Leviathan Armor
Discover the Lich King's Crypt!!
You Killed Golrion! You're developing quite the reputation!
Reach level 24 with Magus
You killed The council demon Kolgren!
You Killed the Portal Guardian Ghenbuuz
Karacaus has fallen, you saved the world!
You Killed Golrion of the Black
Mezirah joined the team!
Get Mezirah to level 23