Old Scratch, also called Old Nick, is often thought to be one being attempting to derail humanity. Old Scratch is also often thought to be a Sidhe Folk or group of Sidhe Folk who have specific rules around deals and rules, and desire to trick people. Despite these speculations, most scholars agree that Old Scratch is a group of beings, and completely native to this world. Why they do what they do is unknown. Humans do know that they look like either a regular person, or a human-goat hybrid, with the legs and horns of a goat with the other features of a human. They almost always keep the horns when they are in the form of a human.
Old Scratch encounters are almost always strange for their victims, and very rarely believed. Each of the stories starts with someone with great piety, or great villainy, and Old Scratch will offer them a binding bargain in exchange for proving their piety or escaping the consequence of their villainy, and then the victim is either consumed by the deal, or manages to perform a trick using the careful rules laid down by Old Scratch.
Common Old Scratch stories tell the tale of the tarot player who was on a hot streak, not sewing or reaping in the fields, but idling in the taverns, relying on their luck. The lucky man stayed idle in the tavern for days until a stranger in a straw hat appeared, and asked to wager on the game. The lucky man smiled as few were willing to play after his luck, and so he began to win. They played all night until the stranger had run out of money. The gambler nodded his appreciation for the wins and waited for the stranger to leave, until the stranger began to shuffle, "One more, against my soul" Old Scratch said. The gambler, not understanding, agreed. When the stranger begin to place the arcana on the table, one at a time, without a single failure, the gambler realized that the stranger's eyes didn't stop burning. As the last trick was taken, the gambler was ripped apart and their soul pulled into Old Scratch. The creature left the tavern, content that their contract had been fulfilled.
This has the classic role of Old Scratch. Old Scratch believes in morality in the same way as the gods, some thinking that Old Scratches are agents of the divine. The Old Scratch almost always has the intent of eating the soul of the victim, and almost always has murder in its heart. Despite this, they almost always have a way out built into their trick. A way out, a single last choice which is a mistake. The gambler can choose to not take the final gamble, the warrior can choose to not wear the armour, the merchant can choose to not guy they grain, and the minstrel can not take the contest. These are all good choices, but people often make the wrong choice when faced with this kind of choice.
Of course, simply making a deal is one thing, the trick Old Scratches have is that they can make the wildest dreams of mortals come true. This is almost always in the form of wealth, or some magical item. However, earning the magic or wealth requires tricking or destroying the Old Scratch in a way that doesn't get the bargainer killed. The easiest way is to engage in a fair contest with Old Scratch, and then, somehow win.
Say Yes: Whenever someone says Yes to a deal with the Old Scratch, the Old Scratch may shade shift one of their skills or stats one shade lighter for the duration of that deal and only during interactions with the person with whom they have the deal. They also increase by 1D the number of cash dice they can offer to the mortal. As the deal gets their hooks into the mortal, the Old Scratch begins to bloat with power, and their offers get more and more grandiose, but they become more and more impossible to defeat.
Font of Goodies: The Old Scratch can generate a number of Cash dice equal to their Bargaining to a mortal. They can also offer magic items at the discretion of the game master, but use the relationship between the item and cash to make that judgement. The goal is that the item in question should match the desire of the person with whom a deal is being struck, and it should stick out as a slightly strange item for the creature to have.
Believable: Old Scratch never lies. Not even once. And somehow this translates to people trusting them. They cannot use the Falsehoods skill, and using the Falsehoods skill against them automatically fails (even in the duel of wits). Rolls forking Falsehoods or being Helped by Falsehoods also fail against Old Scratch. You cannot lie to them or in their presence, and attempting to do so often makes the victim accidentally reveal the hidden truth.
Soul Bearer: Old Scratches are not truly alive. Scholars do not agree if they have a life outside of the pantomime of the deal. They might just appear, do the deal, and then disappear, dying just as finally if they get the soul or not. Despite that, it is known that if Old Scratch can, they will kill the person whom they have made a deal with. Then they will bring their victim's soul into an unpleasant afterlife. This is a horrible experience, and why the Old Scratches choose to do it is completely unknown.
Spiritual Entity: Old Scratches are not ghostly spiritual entities, but they are still creatures who do have a spiritual form in some way. This means that anything which can effect creatures with Spirit Nature can also effect Old Scratch. This means that they can be banished to the otherworld by a priest or kept out via the Fortress Gate, but do not require a Spirit Weapon to harm (as examples). A horseshoe is often used to repel them in this way.
A Burning Wheel Monster Every Week