This is missable
To unlock this you need to progress the Inquisitor
questline, this character visits the Witch Hill (location to the east of your house) every Wrath day (the red Mars symbol).
The Holy Inquisition achievement in Graveyard Keeper worth 7 pointsMet the Lord Inquisitor. An unwavering kind of guy. You definitely wouldn't want to be his enemy.
The first steps are pretty straightforward and after a couple of quests you will unlock the buffet tent where you can sell gold-star Burgers and Beer.
The Night watch achievement in Graveyard Keeper worth 31 pointsGot rid of the guardsmen's ambush. Now you are the Witch Hill Keeper too! The Not a hot dog achievement in Graveyard Keeper worth 33 pointsSold burgers at the burning ceremony. It's a mystery why you didn't make hotdogs.
After a couple of witch burning he will request 3 Dark organs. After this point you will unlock the relevant skill and those organs will start spawning randomly on new corpses. You need to get a dark brain, heart and intestine to progress.
The Match 3 achievement in Graveyard Keeper worth 90 pointsCollected three dark organs. Three in a row! The Inquisition is going to get a prize!
The next week he will tell you that he needs more evidence. At this point you will need to make a choice:
-Tell him about a talking skull (Gerry)
-Tell him about the dark sanctuary beneath the church
-Tell him that you don't know anything
After you pick the first choice you will unlock the achievement.
This is a missable achievement since the choice ends the dialogue with the Inquisitor. After this, to finish his questline and get the object for the portal you need to complete