Atusa's Legs is a quest item in Divinity: Original Sin 2.
Location: Atusa's corpse
When you use Corpse Eater on it: Learn Fortify, and get some lore about about Atusa.
During dialog with Kniles the Flenser: Pacifies him. Fane can acquire the Face Ripper.
You can feed it to Buddy; it will make him upset.
- As of the most recent patch, eating the leg no longer grants a skill.