Devil Binders are persons who have learned to practice the art of binding devils into service.
During the early "Golden Age" of the Demiurges , all manner of arcane knowledge was uncovered and applied including finding ways to make use of the Black Flame of YIS . Some among the demiurges recognized that just as the White Flame of UN was able to be put to work and incarnated as the Aeons ( Angels ), so too it could be possible to harness the Black Flame of YIS.
So the demiurges fought, subdued, masked, bound and named the first devils. The first devils were bound into a set form using a mask. The binding involved giving the devil names, and the resulting devil presumably agreed to a term of service through a contract. The results were devils that could agree to perform service and later seek out new contracts.
Binding devils remains a risky business, but by the time Allison arrived in Throne many thousands of devils had been masked, given identities and bound into form. Rather than having to subdue the very dangerous unbound devils found at the edge of theVoid , it is now possible for sorcerors,vatras, and others who want the services of a bound devil to find them gathered near the King's Road in the Void. Many devils are willing to enter into a contract as they need the nourishment provided by human spirits and others to maintain their power and grow.
Early on in KSBD, Allison traveled to the Void and encountered Three Magisters who were in the middle of negotiating a devil's pact. Wielder of Names 1-13
Allison herself ended up binding a devil to her service, but of course she ended up doing so in the most difficult way possible because of her lack of knowledge and impatience.
Thulsa Drulle was a prominent Devil Binder who wrote the 'Daemonica Maleficum' - a guide to devil kind. Wielder of Names 1-11
“I like thunderclouds. As soon as ye see ’em, ye can be assured when they’ll come around. It’s a damn courtesy when one rolls over the horizon, I tell thee.
It’s the thunderclouds you don’t see that get my worries all astir.”
– Splitpin, devil binder Wielder of Names 4-76