The Line of Forneas: Lore
Among the angels that sided with Lucifer during the revolt, one of them was the angel Forneas, the Angel of Tongues. His initial duties were to give voices to all living things, but when Lucifer questioned the status quo, he was convinced by Paimon to join him, noting that the word of Man should be spread to all the Earth, not just to one garden.
In the resulting battle, Forneas fell, just like the other angels who would later form the Ars Goetia and the royal line of demons. However, the fall affected him differently. When he was found by his fellow demons, his mind was irreversibly shaken, and he was babbling incomprehensibly about "dragons" and hearing the voice of God.
For his bravery and service he became the Grand Marquis. Forneas was given the best care possible to recover from his lapse of mental stability, but the Fall irrevocably damaged him. Though he managed to marry a fellow Goetia and bore a daughter, the periods between his moments of madness decreased year after year. By the time his first grandchild, the heir to the title of Marquis, Andrealphus was born, his moments of lucidity were few and far between. Forneas still techinically has the title of Marquis, however he no longer holds control over his legions and has been retired to his home of Rook's Rest under the care of his staff.
Forneas still rants and raves to himself, still caught in that dreadful day, and the walls of Rook's Rest are scribbled with chalk drawings of what he saw.