Another one? Is that silly guy unsated?
Imagine a perfect athethe's body with a distinctly red shade to it. A pair of leathery wings with spikes on top. Angry, but handsome face with a pair of horns. A demon, he's name is Urspike, he's the demon of the wheel.
All demons have some kind of purpose in their life, most likely a malicious one. Urspike's purpose is very clear, he takes care of a wooden bondage wheel and it's current victim. He's pretty set on his goal, desiring nothing else then to shackle somebody to the wheel and make him work it like a horse for ever and ever.
A ritual to summon him is obviously not too popular, as demonologists are more likely to desire things like 'power over fellow men' or 'forgotten arcane secrets' then 'eternal sweat over a damn wooden wheel'.
When he was invoked, it was either a magican wanting to get rid of someone, as Urspike is known to be patient and impossible to escape, or it was by mistake, like a man who wanted to call 'demon of the will' and laboured meaniglessly for three hundred years. It nontheless improved his will. The wheel.
Uh, whatever. I'm proposing you, the reader, to pay our bored Urspike a visit, and get a pretty extreme masochistic experience. Don't count on much romance, this is pain we're talking about.
It's of course, up to you do decide how you got in his little dimension.