Wisties—also called firefolk by the Ewoks—were a sentient species native to the forest moon of Endor. They were very small (they fit in Ewok palms), radiant creatures of possibly insectoid origin that had an appearance of a moving flame. Fire didn't have anything to do with their luminosity since they could be safely touched by other creatures, but, unlike most species, it was harmless to them. They seemed extremely simple, even non-sentient, but they had a language that consisted of buzzes and a form of government with a Queen as Head of State. During the time the rest of the Galaxy was ruled by the Galactic Empire, Izrina was Queen of the Wisties.
The Tulgah witch Morag once used her arcane Force powers to set the Wisties on fire and bend their will to make them burn the Bright Tree Village and its life-trees. The firefolk set the forest on fire and nearly destroyed the village and more importantly, the Soul Trees. However, even as the Ewoks struggle to fight the fire, they free the firefolk from Morag's spell. In gratitude, they offer to help implement Wicket W. Warrick's plan to airdrop Master Logray's firefoam on the fire by guiding the gliders safely around the dangerous convection currents caused by the forest fire. As a result, the fire is quickly brought under control and the wistie's take the liberty of dropping a bag of firefoam on Morag to humiliate her in revenge.
When the Ewok caravan that accompanied Mace and Cindel Towani in their search for their parents camped in the Endor plains, a group of Wisties were attracted by Logray's candle, carried by Cindel, and leaped into its flame. The candle was considered magical by the Ewoks and its powers must have led the Wisties to this behavior.
Wisties are fond of laughter, and appear to possess some ability to either physically or psychically affect Humans and Ewoks in a manner that provokes it. The sensation has been compared to playful tickling, however the experience is extremely enjoyable and continues to be so long after an actual tickling would have become unpleasant.