Vipture

Vipture was a holy sacrament performed by the earliest of Yuan-Ti clerics who attempted to contact their deity, Snassalla. However, there was in the vicinity an overabundance of wild magic, which caused the holy sacrament to cause a Dispel Magic spell at ninth level to be cast upon the crystal that was to act as a divine conduit, but was actually a crystal created by the Imprisonment spell to detain an extremely powerful fire viper from the Elemental Plane of Fire. When the crystal broke and the fire viper appeared, it understood that the Yuan-Ti believed it to be their goddess. Having no family, no name, no dreams, and liking the look of the Yuan-Ti, the fire viper named itself Snassalla and desperately tried to act as their goddess. After Snassalla found the lost holy relic Ferdiles and returned it to a long lost holy order, the clerics of the order prayed to their god to bless the Snassalla, but their god did more than just that, realizing Snassalla's purpose and dreams, he granted her ascension, and Snassalla truly then became the goddess of Serpentism and the Yuan-Ti.