Spireling Modeth

The Spireling of The Clasp that Vox Machina killed during Demons in Emon.

The "Soul Jars" that contained the souls of Uriel Tal'Dorei and his family were in Modeth's possession when Vox killed him. This, along with them watching Sir Gregory Finch's house, pretty clearly indicates that he (and possibly The Clasp as a whole) were working with the demons / Glabrezu during those events.