Desecrated Cistern (2)

Located near the Prie Dieu close to Mercy Dreams. Continue left until you reach a tall room and you'll find it.

Found in the room where you get the Black Grieving Veil. It's filled with toxic gas and requires you to climb across ladders to reach it.

Flying above some water in a room after using the elevator at Grievance Ascends. Use Taranto to My Sister.

In the very tall elevator shaft. Ride the elevator up from Grievance Ascends, then use Linen of Golden Thread and jump down the shaft, hugging the left wall. When you land on a ledge, use a ranged attack to get it.

Can be acquired late in the game. Requires Silvered Lung of Dolphos and Nail Uprooted from Dirt. From the same tall room where you found the one earlier (#7 above), take the upper left doorway and go through the poison-filled room with these Relics equipped. Flip the lever at the end to reach the Child of Moonlight near a ladder.

Near the Wasteland of the Buried Churches shortcut, in the upper right room. Requires Nail Uprooted from Dirt.