The yuan-ti, despite their love of chaos, have a fairly rigid caste system with slaves at the bottom, with purebloods as ambassadors, builders, artisans, and spies, halfbloods as guardians, warriors, and enforcers, and abominations as the mystics, philosophers, generals, judges, and leaders of a yuan-ti nest. Volo’s Guide to Monsters’ treatment of the yuan-ti is heavily lore-focused, with a section, useful to dungeon masters, on how to design a yuan-ti temple-city. From a tactical standpoint, the only additions are five new variants (!) and a brief subsection headed “Unusual Abilities.” Size. Abominations stand about 5 feet tall when upright, but the total length of their bodies, head to tail, ranges from 10 to as much as 20 feet. Your size is Medium.

This 30-foot diameter pit is 120 feet deep. The pit was built to resemble the pit in which Merrshaulk slumbers. The pit’s sides are unworked stone, and the bottom 20 feet of the pit is obscured by a permanent veil of magical darkness. The floor of the pit is littered with numerous bones and corpses of past sacrifices, obscured by the darkness. Ability Score Increase. When determining your character’s ability scores, increase one score by 2 and increase a different score by 1, or increase three different scores by 1. You can't raise any of your scores above 20. Bruce R. Cordell (April 2004). Expanded Psionics Handbook. ( Wizards of the Coast), p. 218. ISBN 0-7869-3301-1.

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Broodguards, also known as histachii, are humans who have undergone the ritual of transformation but have been found unworthy, degenerating into hairless, near-mindless reptilian monsters. The yuan-ti employ these wretches as watchers over egg-broods and other demeaning tasks. They first appeared as the histachii in Dragon Magazine #151 ("The Ecology of the Yuan-ti" by David Wellham, 1989). Ed Greenwood, Eric L. Boyd, Darrin Drader (July 2004). Serpent Kingdoms. ( Wizards of the Coast), pp. 88–90. ISBN 0-7869-3277-5. James Wyatt, Rob Heinsoo (February 2001). Monster Compendium: Monsters of Faerûn. Edited by Duane Maxwell. ( Wizards of the Coast), pp. 94–96. ISBN 0-7869-1832-2.

Ophidiophobia Aura is a modified version of fear, used for the same reasons, and Shapechanger is as pointless for the anathema as it is for all other yuan-ti variants. This leaves the anathema’s Innate Spellcasting as the feature that most sets it apart.These three variants all possess the normal yuan-ti survival instinct and will retreat when seriously wounded (reduced to 35 hp or fewer), using the Disengage action if they have allies present and the Dash action if they don’t. The best movie villains are the ones you fall in love with. Keith’s book grounds villains in specificity, motivation, and tactics—so much so that players will love to hate ’em. This book will enrich your game immeasurably!” —Matthew Lillard Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. ( Wizards of the Coast), p. 103. ISBN 0-7869-1836-5. The roof of this grand chamber is supported by four columns carved to resemble coiled snakes. The center of the room is dominated by a blood-stained stone altar, atop which rests a curved silver knife. A massive set of double doors stand closed to the east. They are carved with the relief of a Yuan-Ti Abomination stabbing a heart with the very dagger that rests on the altar. Innate Spellcasting. You know the Poison Spray cantrip. You can cast Animal Friendship an unlimited number of times with this trait, but you can target only snakes with it. Starting at 3rd level, you can also cast Suggestion with this trait. Once you cast it, you can't do so again until you finish a long rest. Charisma is your spellcasting ability for these spells.

Mike Mearls, Stephen Schubert, James Wyatt (June 2008). Monster Manual 4th edition. ( Wizards of the Coast), p. 270. ISBN 978-0-7869-4852-9.

Aversion: The yuan-ti creates a compulsion effect targeting one creature within 30 feet. The subject must succeed at a Will save (DC 17) or gain an aversion to snakes for 10 minutes. Affected subjects must stay at least 20 feet from any snake or yuan-ti, alive or dead; if already within 20 feet, they move away. A subject can overcome the compulsion by succeeding at another DC 17 Will save, but still suffers deep anxiety. This causes a -4 reduction to Dexterity until the effect wears off or the subject is no longer within 20 feet of a snake or yuan-ti. This ability is otherwise similar to antipathy as cast by a 16th-level sorcerer.