Burning Fang

There is a dark power rising upon the continent of Kessara. They are spoken of in whispers, and seem to be slowly accruing wealth and power for some dark goal. Codes have been discovered in messages to and from kings and lords, indicating a presence in governance. They appear to be masters of covert operations. They likely use a combination of magic and mundane trickery to gain seats of power, or the ears of high-ranking officials. At this point, it is impossible to say how many individuals currently in power are either one of their agents, willingly cooperating with them, or have been coerced or tricked into furthering their goals. At this point, exactly what those goals are is a mystery. The codes we have broken have only indicated an interest in pyromancy, magical items, and gaining more power.
Less than a score of their members have been discovered across the entire continent. Most agents will willingly commit suicide rather than be taken captive, often with an ingested acid. Of the scant few who have been taken for questioning, nearly all have been either liberated or promptly killed (presumably by a fellow agent) before they could provide any answers. Each one was discovered wearing or holding a small, mildly enchanted accessory or bauble, which masks them from divination magic. Analasys of the bodies indicates they are mostly human, although appear to have been altered in some way. Some have grown patches of scales. Others have vertically-slitted pupils. Some have elongated canine teeth and small venom sacks growing in their mouths. The venom doesn't appear particularly dangerous, and the modifications crude and undeveloped. But they are perhaps related to a case our scholars found reference to in a nearby city: an individual found dead after an accident caused by a particularly aggressive storm. The body recovered was humanoid, but larger than a human, and was covered entirely in snakelike scales. Their neck flared out into a cobra-like hood, and one arm was entirely replaced by what appeared to be an entire snake grafted onto the torso. The body was stolen from the morgue, and the surgeon who headed the investigation went missing the next morning.
This creature appears to have sprung directly out of a children's fairytale. There are oral histories across multiple cultures that have survived through the reign of the Winged Tyrants. They tell of a snake-man who would kidnap children who avoided their chores or stayed out too late after curfew, turning them into his servants. Other stories found in ancient books make mention of a snake god who would, if you were found worthy, grant you ascension to the order of the "Divine Fang." This appears to have been an occult organization which considered the snake to be the perfect animal, and attempted to attain the grace and glory of the snake by transforming into one.
A journal found hidden amongst the pile seems to indicate that this cult was superceded by an offshoot called the "Burning Fang," which seems to also worship the element of fire in addition to the form of the snake. There are mentions of creating a portal to a place consumed by - or made of - fire, and communication with an entity therein. The description of the entity seems to indicate it had a draconic form, with large wings and a horned, scale-covered body. There is also a reference to a holy prophet of this cult. However, every single instance of the individual's name seems to have been burned out of the page. The journal comes to an abrupt end mid-sentence, as the writer mentions this prophet entering this portal to commune with the entity.