The belief in the Radiance, also known as the Sun-in-Splendour, the Light, and the Luminary One, is widespread among the Unknown and Gnolls of the Coalition. Whether it is associated with the sun and moon worship of Temple of the Two Suns, and the Fey of the Tanglelight Forest in general, remains unknown. Regardless, this religion seems to be rather old, since the Ivory Halflings that lived in the New World a long time ago also venerated this deity.

It appears to be associated with Celestials and Aasimar. The Radiance itself must be an actual deity, since its Clerics and Champions derive actual powers and magic from it. 

The Order of the Aureate Roar is a branch of this religion, which includes mostly Catfolk, and places great importance upon Eudosius.

The Cathedral of Grey Grace is an important site of pilgrimage for the religion as a whole, and especially for the Order. It was used by this religion even in the times of the Halflings, who built it in the first place.