MuspelheimIgnis fatuus

Muspelheim, or Ember Therion (Ignis fatuus), are a species of large, flame-based lifeforms of varying intelligences that populate the Everlight on Hyperborea. They dwell in areas of high heat—typically in or around volcanoes—and are generally seclusionary.

Ember Therion are hierarchical and appear to follow a structure not unlike a monarchy; although lesser authorities exist, the overall leaders of the Ember Therion are Níðhöggr and Veðrfölnir. These two, titled the Ember Sovereigns or just the Sovereigns, are a mated dragon-like (Níðhöggr) and phoenix-like (Veðrfölnir) pair. While Ember Therion are among the oldest species on Hyperborea, the Sovereigns are the eldest among the Ember Therion and may even be their originators. It is not known if there have ever been any Sovereigns before them, and evidence of their long existence can be found etched into the geology and other ancient artifacts. It seems they—or at least a version of them—reigned over the Ember Therion back when the current Everlight faced away from Pyr as well. The Ember Therion are likely unaffected by the conditions of the Evernight and may simply migrate to where volcanic activity is highest. 

The Sovereigns have communicated pacts with the Dwarves and Giants, although they do not mingle unless necessary. Unlike said species, the Sovereigns and Ember Therion overall do not communicate through vocalized speech and instead use a form of Sourcery called Runes to affect the ambient energy around them with their intent. They are further known to shape their flames into heiroglyphs when speaking to Sourcery-numb species like the Dwarves, and this is the form that their written word also takes. Ember Therion are evidently masterful practitioners of pyromancy-based Sourcery. 

Overall, Ember Theron resemble that of classically mythical animals or beings. They are born as tiny, kinetic wisps of flame (owing to their scientific name) and may remain as such for life. Ember Therion are made of plasma, with fire-types being the most common, lightning-types uncommon, and quasi-star Ember Therion being very rare. The coloring and intensity of their heat varies and can be affected by age, temperament, and mixed compositions with other organic elements. More complex Ember Therion can shapeshift; some will use this ability to blend or integrate into Dwarven and Giant societies. 

The Giants, Dwarves, and Ember Therion are united against the Fey. The ferocity of the Ember Therion has worked well to keep Avalon at bay, but it is unlikely that Avalon will ever give up their siege due to the richness of resources within Ember Therion territories. The heart of the Muspelheim kingdom is located within Hyperborea's oldest, largest, and most active volcanic site, Ymir.