So, the Yuan-ti in this book are divided up into individual entries, much like the Drow were. But I won’t be covering them individually, partly because I am almost done with this book, partly because the lore in the Yuan-ti PC race write up has to be touched upon in order to gain a new frame of reference for the Yuan-ti Monstrosities presented in this book, and partly because the Yuan-ti Malison warlocks in this book should be discussed as a group for reasons I will talk about later.
The Yuan-ti humanoids are snake people, who may or may not be affiliated with the Yuan-ti Monstrosities. The Monstrosities are the snake people who are trying to topple governments, and kidnap humanoids in order to turn them into more monsters. There are no more references to the caste system (outside of the allusions to slavery with the Broodguard), nor any references to their lack of emotions.
Additionally, the type 4 and type 5 Malisons were not reprinted or even hinted at for this book.
The Anathema were once Yuan-ti Abominations, but underwent a ritual with the intent to bestow godhood upon them. Anathema are not quite divine, but consider themselves demigods, and expect everyone else to act like it. An Anathema can lead a city, or even multiple cities, and uses all the resources that implies to wage war.
In combat the Anathema is a CR 12 melee controller, boasting both a climb speed and a swim speed to round out their mobility. They possess both the Darkness spell and Blindsense, allowing them to do the Warlock tactic, but also have a grappling attack in their Huge Constrictor form, allowing them to keep someone in the Darkness with them, making said tactic much more effective. Their aura of fear provides another control option, which can last quite a long time, should the victim not make their save. And finally, they boast the Polymorph spell, which can be used as a control option, or as beefy backup.
In the changeover, the Anathema lost the Divine Word spell (a big loss). Additionally, their multiattack was overhauled, losing one of their attacks. They also lost the Shapechanger tag (Seriously WotC! Standardize your tags and make them index friendly, there was no reason for that change other than making things harder on the DM than they should be!), but kept the ability to change their shape into a huge snake, albeit without the reference to any magic spell, which prevents them from being counterspelled or having to use concentration at least. Their advantage on perception was folded into their perception score (allowing them to keep the bonus even when they change shape into something with one head), and on a positive note, they had their climb and swim speeds buffed by 10’ each, to a total of 40’
The Broodguards are all that remain of humanoids who were transformed by a ritual, making them dumb muscle and totally subservient to the Yuan-ti. Broodguards can still comprehend and carry out assigned tasks, such as guard duty, and are often left to watch over Yuan-ti eggs (hence their name). The ritual for making a Broodguard is quite well documented by this book, even going so far as providing counters to prevent the ritual from completing.
But mostly, Broodguards only exist to be meatshields for the other Yuan-ti, which is somewhat reflected in their stat block. A CR 2 melee unit with an Average speed, their most notable features are their Reckless ability, and their collection of immunities to status effects. You would think that they could use some form of ranged weaponry (maybe even a poison spit attack), but they don’t.
In the changeover, Broodguards were stripped of their Humanoid status and turned fully into Monstrosities. They also had their Mental Resistance power replaced with outright immunities.
Yuan-ti Malison Warlocks (with a tag no less!)
The rest of the Yuan-ti in this book are Yuan-ti Malisons* who have formed various pacts with the Yuan-ti gods, but also act as priests. Each type of 1-3 is represented with a different pact. Though it would be relatively easy to retrofit any of the god-pacts with any of the Malison-types by comparing and contrasting the MM entry with their stat block, I have to admit that the Warlocks fit quite well with the pre-selected types. Of note, all of these warlocks lost the shapechanger tag, but gained the warlock tag. More importantly, the wording of their Change Shape Bonus Action allows them to use their Spectral Fangs attack, which can be quite the surprise when facing down an otherwise normal snake, and they can even use their multiattack with it, making their snake forms more deadly. All of these warlocks have Devil’s sight, but only the Nightmare Speaker has the ability to pair it with Darkness ( handy if you are making a group of them).
*See the MM, but they will likely be changed when that book is revised as well.
Yuan-ti Mind Whisperer
Mind Whisperers are type 1 Malisons who entered a pact with Sseth, the Sibilant Death. The primary god of the Yuan-ti, and the one responsible for their ongoing schemes to take over the world. As devouts of Sseth, Mind Whisperers have a reputation for being extra sneaky and backstabby.
In combat, the CR 4 Mind Whisperer functions as an artillery with a bit of control on the side. Their primary form of control is the Hypnotic Pattern spell, which can be quite effective if they can prevent their allies from striking the wrong foe. The rest of their kit is tailored to Social encounters, which is nice when dealing with a politically active opponent.
In the changeover, the Mind Whisperer was overhauled, changing from a melee focused unit with lots of mind control potential to a ranged unit that focuses on incapacitation.
Yuan-ti Nightmare Speaker
Nightmare speakers are Type 3 Malisons who made a pact with Dendar the Night Serpent. They are oracles of sorts, and love to torture people into having nightmares, which they can interpret as prophecies. While the Mind Whisperer’s primary mechanic was Charm. The Nightmare Speaker’s primary mechanic is Fear.
In combat, the CR 4 Nightmare Speakers are melee controllers, though you have to be careful with their concentration, as even their non-spell Invoke Nightmare attack has it. As for interesting tactics, they can use their signature fear attack even while in snake form, allowing for an ambush. Additionally, The Nightmare Speaker can fear one target and constrict another, giving their team a two-for-one control special. Should their control options prove to be less than effective, they can always fall back on Darkness for the infamous Warlock combo while blasting away with Spectral Fangs.
In the changeover, the Nightmare Speaker did lose a bit of their control potential (notably the Hunger of Hadar and Hold Person spells). But the extra spell slots more than makes up for it.
Yuan-ti Pit Master
Pit Masters are type 2 Malison priests of the sleeping god Merrshaulk, who was the first god of the Yuan-ti but has fallen out of favor on account of how he is sleeping on the job most of the time. In an attempt to wake him up, the Pit Masters perform lots of ritual sacrifices. The main thing you are going to notice about them is their lack of hands, seeing as how their arms are just snakes (they do have Mage Hand to somewhat compensate). Their gimmicks are sleep and poison (but not the poisoned condition, strangely). And they are notable for having the most dangerous snake form of these warlocks.
In combat, the CR 5 Pit Master is likely to open up with their Merrshaulk’s Slumber attack, even while in snake form, which can cause up to 5 targets to fall asleep. That can be followed up with Hold Person for a bit more control. Making them a slightly more dangerous take on the Mind Whisperer, but only for the sake of Combat.
In the changeover, the Pit master had their skills recalculated using the right numbers, resulting in a small boost.