Hell in Freeport Prestige Classes (2001)

From Introduction:

The blackthorn, crusader, grayback, and manikin are new prestige classes with special requirements. All four require a special initiation (detailed in the entries), and all four change the character’s base type from humanoid to something else: construct, elemental, outsider, or even plant.

Note that these classes are NOT intended for use by PCs—they are far more powerful than traditional prestige classes, and are designed to round out four very specific cultures within the infernal prison of the Forge (see Hell in Freeport). If the DM allows his players to take these classes, he should impose a 20% penalty on earned experience so that they advance more slowly than conventional characters.