The Aussig Ghoul

Note: Keep in mind that all background information is based solely on the tortured confessions of an old, and obviously deranged recluse.

During the Crusade against the Hussites in 1427, Simon Bernières was among a small group of English soldiers fleeing the aftermath of the battle of Aussig. Seeking shelter from a storm, the group was drawn to firelight coming from inside a deep mountain cave, which they found to be inhabited by what he later described as "heathen madmen" who howled like wild beasts and set upon his group. The soldiers were forced to defend themselves and quickly slew their attackers. The cave, they soon discovered, was filled with mounds of gnawed bones and fragments of human corpses, along with an ancient and peculiar black alter on which sat a daemonic horned skull of a particularly repellent nature. After passing the night near the mouth of the cave Simon took possession of the skull, and eventually returning to England.

Nothing was heard of the former soldier until 1439 when surviving records from the western town of Hartlepool, mention the arrest of one "Symon Berneres", for the violent murder of a husband and wife in their beds in a most "fowle and unholy manner".

Details of his arrest and interrogation are sketchy, but the record does state that the dilapidated forest shack where he sheltered was found to be strewn with the remains of four people looted from local burying grounds. One of which had been cooked and partly eaten. A horned, "demons" skull was found perched in a place of prominence overlooking the scene.

At his trial, Simon confessed that the skull spoke to him. It  was filled with a ravenous hunger he said, and it harried and worried his mind day and night, forcing him to provide it with "meat", which he shared. Animal at first, and later, human. In exchange he claimed the daemon rendered him invisible to the eyes of the kings patrols as he poached the nearby forest.

Simon was hung a month later.

The skull somehow found its way to the local Church of Our Lord where it remained in a hidden recess above the main doors for the next 400 years. The church was dissolved due to an unrecorded scandal in 1807. The skull, and church records were stored deep in the cellars of Hartlepool Castle, which had its own unsavory history. 
The skull was photographed twice In 1915 as part of a magazine article, but information as to its location was lost due to the destruction of the magazines office and the death of the writer/photographers in a German Zepplin raid. 
Eventually the skull and legal records were rediscovered during renovation at the castle last year and were donated to the museum.

Recent studies estimated the skull to be from 1800-2100 years old. Whether the skull belongs to a non-human entity, or is the result of extensive inbreeding and genetic degeneration is still unclear. The bone layer is thicker than a normal humans, and has trace elements of chitinous material. The peculiar scarring on the crown is astonishingly similar to a design found in many eldrich texts, depicted a primitive star map showing the positioning of  the major stars when they are 'right', heralding the return of the Old Ones.

So far there are no reports of it asking to be fed.