Withermoore's Soul Jar is a Quest in Divinity: Original Sin II.
I agree to help Lord Withermoore destory the Soul Jar, he told me of a lever located on the main floor of Fort Joy.
- Find and destroy the Soul Jar of Lord Withermoore.
- Play hide and seek with the little child called Mody. He can be found in the Caverns on the south of Fort Joy.
- After you've found Mody, he will ask you to meet with his secret friend. You'll need shovel or a Lizard to uncover the ladder.
- Remove the spear on the chest of Lord Withermoore. After that, he will ask you to destroy the Soul Jar.
- Inside Fort Joy Prison, there is a secret lever at x316, y673 (on your left hand side when you enter the main gate). Pulling it will open a hatch leading to an Ancient Passage filled with traps. You can put the nearby vases on the vents to disarm them.
- Following the passage will lead you to a room filled with different Withermoore Soul Jars. The one you're looking to break is Withermoore the Supplicant. This frees the soul of Withermoore and updates your quest log.
- The other jars will spawn enemies or traps. Cold-Hearted Soul Jar freezes the entire room's floor (and maybe some of your characters). Yellow-Bellied spawns 4 skeleton guardians on the sides of the room. Sage spawns 3 skeleton guardians. Noxious is an explosion trap.