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