Here is the full list of all 40 Tainted Grail: Conquest achievements.
Slay the First Guardian
Slay the Second Guardian
Slay the Third Guardian
Reach level 20 with the Summoner
Reach level 20 with the Necromancer
Reach level 20 with the Blood Mage
Reach level 20 with the Wyrdhunter
Reach level 20 with the Pathfinder
Reach level 20 with the Berserker
Reach level 20 with the Sentinel
Reach level 20 with the Zealot
Reach level 20 with the Apostate
Recruit the Blacksmith
Recruit the Ghost
Recruit the Seamstress
Recruit the Scientist
Recruit the Candlemaker
Recruit the Master-At-Arms
Recruit the Bard
Find your furry companion
Kill your first Treasure Guardian
Kill 3 Treasure Guardians in a single run.
Reach any place at the leaderboard.
Win the fight in the tutorial.
Win a fight in one turn.
Win a fight having less than 5% HP.
Upgrade a Quest Card
Draw your entire deck in one turn.
Play your entire deck in one turn.
Stun an enemy that intends to attack you with 10 or more Hits.
Get enemy's Armor to -500.
Deal more than 3000 damage in a single Hit.
Spend all Energy without dealing any damage 3 turns in a row.
Finish a run fighting in less than 15 combat encounters.
Die and immediately start a new run.
Use 3 items in one turn.
Use 10 items in a single combat.
Light a wyrdcandle to an Ultra level in combat.
Win a run without using Healing Potions in combat.
Win a run with 8 or less cards in your deck.