I first saw the word Ördög in the pages of Dracula. It was the Hungarian word for Devil I came to learn. As is my habit, I wrote the name on my bookmark and went on. It was not till later that I saw the name again that I starting thinking it would make a good devil-type.
The Ördög is part of the Hungarian folk tradition. They appear much as a satyr or faun; humanoid with the upper torso of a human male and lower portions of a goat. Their hooves are black and cloven. Their features are bestial and they have long ram-like horns. It is sometimes remarked that the best way to know the difference between an Ördög and a Satyr is by the size of their horns, but this is not always foolproof.
The Ördög also has a long black tail that ends in a blade. They can't attack with it, but it looks frightening. Another part of the ördög that is frightening is their overtly large phallus.
The Ördög shares more than surface similarities to the satyr. Like the satyr, the ördög can be found in rural or wooded areas. Also, the ördög is summoned up most often to partake in the sabbats and rituals of witches. These devils partake in the infamous orgy-like sabbats of witches, held at midnight. Children born to the witches after these orgies become ördög themselves if male or witches if female.
One of the more famous (or infamous) Ördög was Caliban, son of Sycorax.
An Ördög can appear as human male, albeit one with thick black hair and black eyes, or as a large fox.
Some occult scholars believe that ördög share the same relationship to hags as satyr's do with nymphs.
Consequently, the offspring of an ördög and a nymph is a Forlarren.
Since today is Sword & Wizardry Day, here is the ördög in S&W format.
Hit Dice: 6
Armor Class: 4 
Attacks: 2 claws (1d6)
Special: Magic resistance (45%), regenerate (1 hp/round), shape change (human, fox)
Ördög are among the lowest of the Shedim. They spend quite a bit of time in the prime material plane where they work as messengers for higher level demons. Much like imps, they can teach witches of the Malefic, Diabolic or Demonic traditions spells. A witch can learn one new spell per interaction with an Ördög; once per sabbat. The ördög needs payment for learning this new spell; usually in the form of a sacrifice or sexual congress.
Ördög are wild demons, they attack with their claws like that of animal; often ignoring weapons even when they are handy.
Swords & Wizardry post is later today.