Ryn

 is a tiefling planar studies specialist and a member of the Arcana Pansophical. She has been mentioned but not appeared onstream.

Background
She is often traveling between the realms to complete her research. At some point, she gave a Spell Scroll of Planeshift and a tuning fork attuned to the Elemental Plane of Fire to Yussa Errenis.

While fleeing from the Cerberus Assembly, the Mighty Nein used the Spell Scroll gifted to Yussa and found themselves in the Plane of Fire, inside what appeared to be a field lab belonging to Ryn. There they found Ryn's notes pertaining to the Planes of Existence.