Religions often argue about the origin and nature of demons. Some say that they are extradimensional beings inimical to men. Some say they are the infernal spawn of the gods of darkness, who want nothing more than to corrupt and take mortal souls.
And some, who know of something called the Court of a Thousand and Nine Sorrows, say that there are demons walking the world who were once mortals themselves.
The Thralls of Sorrow are the lesser demons who serve the Court. As the Sorrows embody aspects of personality, so do their Thralls. However, they are subservient to the Sorrows, and must obey their master. Some don’t even have a will of their own, and must be ordered to do anything.
Thralls look mostly like regular people. However, there is always something "off" or "wrong" about them, and they almost always make people uncomfortable; they are less adept at concealing their nature than their greater counterparts.
Thralls generally have lesser versions of the same abilities their masters do, or lesser abilities that complement the master’s. Unlike the Sorrows, they CAN be destroyed permanently, but it is certainly not easy.
Each Thrall serves the Sorrow of whatever aspect is the closest match to their own aspect. Among the Sorrows, they are widely considered servants, go-fers, meat-shields/cannon fodder, and, occasionally, victims, depending on the Sorrow.
With a very few exceptions, Thralls do not like their masters, but they can’t do anything about it; they must obey.
Like the Sorrows, Thralls were once mortals who became… something else. There are two distinct types of Thralls, based on the way they became what they are now.
The Late Ones were mortals who had the potential to become Sorrows themselves… but someone else beat them to it. The metaphysical laws that govern the Sorrows dictate that there can be only one Sorrow of a given aspect at a time. These Thralls are often held in contempt by their masters, and are likely to have their own agendas. It is theorized that a Late One could ascend to full Sorrowhood if they were in the right place at the right time (assuming their master was temporarily killed), but it’s never happened, as far as anyone knows.
The Corrupted Ones are a completely different matter, however. The creation of a Sorrow involves powerful, and sometimes terrible, forces that can leave permanent scars on the location, certain objects… and people. These Thralls were too close when a Sorrow was born, and something resonated enough that the backlash changed them as well. Usually, they’re a little mad, in one way or another.
Additional Ideas (1)
The Schoolmaster is the Corrupted Thrall of Curiosity. As a mortal, he owned a school that produced many reknowned scholars. He himself was a man devoted to knowledge. One of his students was Ran, the small boy he had adopted as his own son. Ran was very, very curious, which sometimes caused problems, but the Schoolmaster was usually able to stop the problem before it started.
However, one day he returned to his private chambers after one of his classes and found Ran perched on the back of a chair, reaching for a book on a high shelf. Before the Schoolmaster could do or say anything, Ran fell, striking his head on a nearby table, and died. If the matter had ended there, the Schoolmaster would have mourned and eventually gone on with his life. But Ran became the Sorrow of Curiosity, and the resulting forces wrenched the Schoolmaster into something else.
There is very little of the Schoolmaster's original identity left; he doesn't even remember his own name. He is usually found with Ran, posing as his father; he doesn't like to leave his master alone. He is curious himself, but relies on Ran to tell him what to do.
He is scrawny, with a hawk-nose, generally uncombed black hair, and a sort of vague expression. His hands always have inkstains on them, and his clothes always seem to smell of chalk dust. If he comes into contact with something for very long, he always manages to smear ink on it or correct it, even though no one will observe him doing so.
Most people he encounters think him a relatively harmless madman, but give him and his "son" a wide berth. A few who have tried to remove Ran from his care for the boy's own good have found out that's not a good idea.