Collect 8 batches of Cursed Ooze from the Ruins of Constellas.
Yeah, yeah, your stuck-up mage friend there hit it on the nose. The imps over at Shadowlurk Ridge are hiding the key to the satyr's barrier in the nether. It's right there, but you can't see it or touch it unless you're shifted.
I guess you're out of luck though, because only imps can phase shift! So you should just close your eyes, turn around, and let me go...
It was just a joke! Don't hurt me! I'll need slime from the cursed oozes around these ruins. Bring me enough to cover you from head to toe!