Cult of the Morninglord
The Cult of the Morninglord in essence represents the corruption of the worship of Lathendar Morninglord from Faerun (in the Forgotten Realms campaign setting). While the cult steadfastly insists that their worship is not such a corruption, and that the Morninglord is a native deity of the Core's own. Regardless of the truth of the matter, which is unclear at best with Ravenloft's usually distant Godly powers, most outside of the church would consider it thus - given the striking similarities of the iconography and tenets of the faith of Lathendar and that of the Morninglord.
Origin
The Cult of the Morninglord came into being with the tales of a Faerunian outlander named Martyn Pelkar, whom, at the age of ten was misted, and spared from Strahd and his vampires at the insistance of another vampire in Strahd's retinue - Jander Sunstar. Mistaking the gold elf counternance of Jander for Lathendar Morninglord, the child would go on to found the cult of the Morninglord in Barovia. Many outside of the cult called Martyn the mad, for the child's insistence that this was the divine intervention of the Morninglord
Social Standing in Zeidenberg
Despite the debate of its origins and the general outside disregard for their insistence that the Morninglord is not Lathendar, the cult is generally looked upon favourably by those in Barovia that give it any notice at all. It is generally known for acts of charity and benevolence, and those that come into severe illness, homelessness, or hardship, can often find themselves succor in their modest sanctuary.
However, this charity cuts both ways, and they have little standing with the garda and their masters, for they are also known to extend this charity to the gundarakites - many of whom are no doubt rebels. Politically, the Cult is essentially powerless as a result of this, at least in terms of hard power - they can still facilitate change towards their ends through their popularity with the common folk.
Dogma
The Morninglord is a deity of hope and optimism, and his church reflects this. He asks his flock but to extend goodwill and kindness to each other, and to not relinquish hope. A steadfast foe of all undead, the Morninglord is popular among native adventurers whom face such foes.
Notably, the Morninglord is not a lawful deity; his church often espouses that the laws of man cannot be trusted to administer justice, and such shall only come with the Dawn. This dogma is one they keep to themselves, for the most part, but a significant source of tension with the Burgomaster and their servants the garda.
The Morninglord
The Morninglord is usually depicted as a gold elven male of Faerunian features, glowing or comprised of light. Upon his lips is blood, which the church would teach represents that even the most goodly have some darkness within, and we should not lose hope. This has lead to a common saying of the church being: "May thy lips be cleansed," signalling a hope for the defeat of this inner darkness.