For many generations the people of Eldreth believed that the "Faerie Queen Titania," her consort "Oberon" and their "Faerie Court" created and ruled the world until interloper deities began to appear with the arrival of immigrant peoples to Eldreth. Encouraged to believe the myths and legends of "Titania" and her "Faerie Court," the mortals of Eldreth worshipped them as gods.
In fact, "Titania" and her court do not exist. Instead, the identity of "Titania" was used by several powers, including the archfey Tiandra, Summer Queen of the Court of Stars, and the deity Sehanine Moonbow, among others, to advance their interests on Eldreth. Likewise "Oberon" was an identity used by the archfey Oran, known as the Green Lord, and the deity Corellon Larethian, among others.
The powers involved in this deceit had gained great influence over the mortals of Elderth through the dominance of "Titania" and her court. Though they often worked at cross-purposes (incidentally creating conflicting stories regarding "Titanis's" goals and history with Eldreth) they cooperated to maintain the fiction of the "Faerie Queen." Their greatest tool was the Gesaedere, a mantle of power over Eldreth's weave of fate created during Eldreth's pre-history by the Court of Stars and the Seldarine, through which "Titania" often worked her will upon Eldreth.
It was when the Gesaedere was seized by the Dark Plea, followed by the mantle's transformation into a self-willed artifact by the Knights of the Sword Coast and its disappearance shortly thereafter into the possession of a stellar dragon upon the Dark Plea's final destruction, that the fiction of "Titania" and her court began to unravel. Within a generation, "Titania" and her court had fallen from favor as objects of mortal worship. By the end of High King Eobryn's reign, stories of "Titania," "Oberon," and their court were seen as allegorical representations of the Court of Stars and the Seldarine, and were studied by scholars as interesting fictions. The worship of the "Faerie Queen" had come to an end.
However, the deep connection between much of Eldreth and the Feywild remains. The people known as Aelfirians are strongly entwined with the intrigues of the archfey, who are afforded a respect (now under their own names) which borders on worship in some quarters. The Seldarine of Arvandor (also now under their own names) are afforded a similar reverence by Aelfirians. Both archfey and Seldarine are unaligned, but most of both groups are believed to be generally benign towards Aelfirians.
Despite their reverence towards the archfey and Seldarine, the Aelfirians actual worship is directed to the Celtic pantheon.
The Norse gods are the patrons of the Northmen, who follow this pantheon almost exclusively, and rarely share the Aelfirians' reverence for the archfey and Seldarine. The humans of Veldreth also reject the archfey and the Seldarine, worshipping the Great Spirit along with several Norse divinities and lesser spirits as manifestations and servants of the Great Spirit.
The gnomish divinities which share Arvandor and the dwarven deities of Dwarfhome are worshipped by their own people, and by those humans who live and work closely with the Quiet Folk or the Stout Folk, respectively.
Deities worshipped in the Southern Empire include the PHB/DMG "core" divinties and the sun god Amaunator, held in high honor as the patron of the Code.
Finally, Entropy, known as the Dark God, has sunk its roots deep into Eldreth.
The nature of this terrible entity is a mystery, and it is greatly feared.