Nahdrah demons were blue skinned in appearance and wore metal face masks. Every few years, their heads were disgorged and needed to be replaced. They enjoyed puzzles and used the most difficult ones in order to find worthy minds to replace their heads.
Impressed by his article on the Net on the comparison of the fusion of the DNA in the populations of demons with three legs, their first choice was Wesley Wyndam-Pryce. However, deciphering the motives on their togas, Winifred Burkle impresses them even more. They hired her to solve such a puzzle and planned to use her head to replace their dying prince's.