Greater serpent men are the rulers and high priests of the clans. The clan leaders always take on the title of king or queen, and they always have maximum hit points. They are accompanied by 3-5 common serpent men with maximum hit points acting as their bodyguards. High priests are often aided by 1-3 sub-priests, which can be common serpent men. Only greater serpent men can be high priests.

The priests can perform rituals that requires a sacrifice of a living being; humans are preferred, but other humanoids work as well. The total number of hit dice of the victims (more than one may be sacrificed at one time) would grant a Cleric spell of equal spell level. Victims with less than 1 hit die count as a half-level, so two zero-level humans would be needed to cast a first-level spell. Rituals include healing, animate dead, area effect spells, or summoning otherworldly beings. Only high priests can perform rituals, but they need the assistance of the sub-priests for the various tasks required in the ritual.