Here is the full list of all 30 Curse of the Dead Gods achievements.
Write all Bestiary entries with their complete sketches
Unlock all Weapon Altars upgrades
Become the new Champion of Death
Equip a hidden Champion weapon
Equip the three weapons slots with Cursed weapons
Defeat Clovis Pardieux, Champion of Death
Complete 10 different "Special Events"
Complete any exploration with 50 or more Perception
Unlock 20 Blessings of the Dead Gods
Complete any exploration with 50 or more Dexterity
Make 10 Blood Offerings during a single exploration
Unlock 20 Forsaken Weapons
Defeat the Dark Avatar of the Serpent
Complete any exploration with 50 or more Constitution
Defeat Ratyapu, the Abomination
Get 3 successful Parries in less than 2 seconds
Defeat the Dark Avatar of the Jaguar
Defeat Litz & Nepac, the Cursed Twins
Defeat the Dark Avatar of the Eagle
Lift the Final Curse
Defeat Malok paal, the Flesh Monstrosity
Defeat K'ax taca, High Lord of the Storm
Unlock 5 Forsaken Weapons
Defeat Xucat', the Witch
Write 5 Bestiary entries
Defeat Xak'olchir, the Blood Hunter
Achieve a x10 "Greed Kill" series
Unlock a Blessing of the Dead Gods
Start a "Special Event"
Complete the room of Trials