There are two reasons that the Hellraiser series has spawned a bazillion sequels, books, comics and a possible remake. First, Clive Barker is wildly imaginative and can seduce the dark with his poetic and beautifully perverse reverie. Second, the Cenobites.
The word cenobite means 'a member of a monastic community' but the Cenobites in Barker's stories and the Hellraiser film series are the dark guardians of an unholy order. Barker's novella The Hellbound Heart describes the Cenobites as Theologians of the Order of the Gash (or simply, The Gash) and The Hierophants. These creatures can only be summoned through the Schism by a device such as the Lament Configuration. Yeah, that's the infamous puzzle box. Many of the Cenobites were once human but their insatiable appetite led them to open the box -- transforming them into the mutilated figures we know. Purveyors and explorers of the flesh, the Cenobites are called by those who seek unearthly delights and become trapped in an endless cycle of torture and pain.
In the films, Doug Bradley portrays the most well known Cenobite, Pinhead, who is considered the leader of the pack. A former Captain during the First World War, he lost his faith in humanity and sought comfort in the cruel and unusual. Pinhead boasts a head full of pins that have been hammered into his skull, hooks and chains galore (also his favorite weapon) and a torso of peeling flesh. Even though I totally dig his leather gown, I'm not sure that's enough to make me open the box. Other Cenobites include the Chatterer, the Siamese Twins, Butterball and Stitch. Each one has a sinister set of mutilations that would make Bob Flanagan jealous.