Ring of the Tiny Fiend

Gift from Raeanndra after you rescue her using Spectacles of Spectacle during Zaviak's Vision Quest in Chapter 10.

In-game description
"Every elemental plane has its own native creatures, the lowest of which are the mephits. These imp-like creatures appear composed of whatever element dominates their home plane. They are remarkably clever for such unintelligent creatures and can often be found serving as wizard familiars. This ornate gold ring displays four chips of precious stone—emerald, ruby, sapphire, and diamond—surrounding a grinning mephit's face."