The Trapped god Avandra
Nephelim is trapped in another plane that opens up from Delad’s dimensional knife.
He/she at first glance seems to be a child in nature with her quick, jittery words and fast thought process but later one realizes that he/she/it is either a gnome or a halfling.
Nephelim can affect the plane around his or her own will but can’t get out of it. The party can come into the dimension for rest and sometimes able to buy gear and magic items from the fey (when he/she is in a good mood and wants something shiny)
Nephelim has been taking care of Irrbryn while Delad has been adventuring. It was finally revealed in a game of truth or dare that Nephelim is actually the god Avandra who was imprisoned here by Sehanine. She helps the heroes by giving them the scroll “Exorcism” in order to banish Stondylus once and for all.