From publisher blurb:
Learn of the diabolical knights that serve as the elite soldiers and enforcers for the Overking of the Great Kingdom. These warriors, augmented by demonic magics are stripped of all individuality and humanity to become the perfect instruments of tyranny — soulless, relentless, and bound to the will of their Overking.
This 5 page Greyhawk mini-supplement includes:
The Lore of the Fiend-Knights. Learn about the creation of the Fiend-Knights by the Overking and his court mages, including some short notes by the Fiend-Sage of Rel Astra himself.
2 Full Variants. A standard Fiend-Knight and a higher-ranking Fiend-Knight both ready to go challenge your players.
3 Additional Variations. Additional abilities from the regiments of the Fiend-Knights, the Howlers, the Bolters and the relentless Pointers.
Magic Items. Fiendish items that are literally too hot to handle.
Artwork. Art for both monster entries and the heraldic shield of a Fiend-Knight. (Some artwork is made by AI, others such as the Heraldic Shield of the Fiend-Knights and the layout art by the authors).