When a creature solves one of the many boxes (Carborro, the Lament Configuration, etc), a small group of Cenobites arrives. If Leviathan, god of the Labyrinth, believes the creature is worthy to become a Cenobite, they are taken to the center of the Labyrinth to be remade in a Transformation Chamber operated by the Engineer. The alteration is excruciatingly painful as the victim's body is excessively mutilated as they are infused with the power of the Leviathan into a devil. When finished, what emerges is a twisted caricature of the original person, often tailored with perversions of aspects from their original persona.
If the creature is not deemed worthy, they will either still be taken into the Labryinth, where they will spend all eternity in torment, or be destroyed on the spot. Only by reversing the completion of a LeMarchand Box can a potential victim avoid being taken by the Cenobites. All Cenobites are bound to the LeMarchand boxes and subject to their rules: a box had to be opened for a Cenobite to attack, and only the one who had opened the box was a legitimate target.