Here is the full list of all 24 Nadir: A Grimdark Deckbuilder achievements.
Play the Saint's Blood card
Defeat Fury
Defeat Moloch
Defeat King in Yellow
Defeat Chernobog
Defeat Asmodeus
Defeat Minos
Earn any Desires for the first time
Defeat Lilith
Earn any Idols for the first time
Defeat Koschei the Immortal
Defeat Abaddon
Earn any Skulls for the first time
Defeat the Gunnery Demon
Defeat Feaster from Afar
Earn any Filth for the first time
Earn any Relics for the first time
Defeat Beelzebub
Defeat Belzebub
Obtain any Rare card
Possess a Damned as a reward
Purchase any card in the shop
Unlock Vlad Tepes as a playable character
Unlock Hernan Cortes as a playable character