Grave of the Tyrants Map & Location
The Grave of the Tyrants sits in the northwest of the map, with the entrance around 28.2, 29.0 — it's one of the trickier caves to spot, tucked against a cliff wall when you look southwest. It's a water-rich cave (one of the better base spots on the map) and is sometimes called the Blue Cave for its blue-mushroom-lit corridors.
Head in and follow the trail down on the right side until you hit water, then follow the stream into a corridor marked with blue mushrooms. Keep going until you reach a giant ribcage — your first fork. Either path works, but the left path is faster. Keep left and you'll reach the final chamber with the Artifact of the Crag (and the Scorched Torch skin).