Merrshaulk

Merrshaulk
A flying snake with bare fangs
Alignment	Chaotic Evil
Divine Rank	Intermediate God
Pantheon	Yuan-ti
Portfolio	Beasts, Predators, Somnolence
Domains	Animal, Chaos, Charm, Destruction, Fate, Plant, Scalykind, War
Home Plane	Smargard (Abyss)
Worshippers	Yuan-ti, Hunters
Favoured Weapon	Longsword

Merrshaulk is one of the main deities of the Yuan-ti species in the core D&D setting, but in the Forgotten Realms setting, Merrshaulk is just one in a line of snake deities since they tend to fall asleep and get replaced.

History

In the beginning, there was just one deific overbeing: the World Serpent, (called "Mok'Slyk" in the Greyhawk setting) which for D&D is practically the Ouroboros, a creature of incalculable and eternal power on a scale similar to the Lady of Pain or Ao and was worshipped by the progenitor races.

Over time, those ancient empires fragmented into smaller kingdoms who brought unique aspects of worship with them, breaking the World Serpent into smaller deities, forgetting the original World Serpent and depriving it of power to the point that it no longer grants spells or answers prayers. In fact, the only being suspected to have any contact with the old "Serpent" is Vecna, who was supposedly trained by it. Though that may very well be just some mad ramblings.

Merrshaulk was the aspect of the World Serpent who took the portfolio of actual snakes and is worshipped by the Yuan-ti. Furthermore, Merrshaulk is a particularly nasty deity who demanded constant sacrifice, preferably willing Yuan-ti, but content to accept unwilling prisoners from other races if provided in bulk.

Sseth

Sseth
A flying snake with bare fangs
Aliases	The Silibant Death, Slitherer Supreme
Alignment	Chaotic Evil
Divine Rank	Intermediate God
Pantheon	Yuan-ti, Chultan
Portfolio	Poison, Secrets, Somnolence
Domains	Air, Animal, Chaos, Evil, Knowledge, Magic, Planning, Scalykind, Trickery
Home Plane	Great Wheel/World Tree: Smargard (Abyss) World Axis: City of Serpents (Towers of Night)
Worshippers	Yuan-ti, Scalykind
Favoured Weapon	Scimitar

"Hey hey people."

– *BLAM* Not that Sseth

In the Forgotten Realms, Merrshaulk has been replaced by Sseth, the Slitherer Supreme.

During an early period of Faerun's history, Merrshaulk had grown tired and bored, and started forgetting to answer prayers or grant spells. Quite possibly because the rate of sacrifices offered had slowed to a trickle because younger races were starting to form their own empires and openly fighting back against the Yuan-ti.

Then one day, a winged Yuan-ti with a talent for giving speeches showed up and declared that he was the avatar of Merrshaulk reborn and that the Yuan-ti should start worshipping him instead. So when faced with the fact that this new guy would grant their spells and sleepy old Merrshaulk would not, the choice was clear.

Sseth was also probably a better deity politically compared to his predecessor, and was considerably more active during his tenure as the lord of snakes. While the new guy still demanded a constant flow of sacrifices; where the old religion was very primal and focussed on survival and animalistic hunger, Sseth by contrast was a god of secrets and intrigue. His rewards would be whispers of knowledge to grant advantage and further ambition. Sseth also taught his followers the magical rituals for transforming their human slaves into lesser Yuan-Ti called Histachii (or Broodguards). Sseth also quietly consumed the patron deity of the human city-state of Hlondeth: Varae and began answering prayers in their name. Though initially this was kept secret, Yuan-Ti cultists infiltrated the city and eventually took over it, spreading the faith of Varae (as Sseth) as far south as Calimshan.

However, some Yuan-ti disliked the new direction the church went in, finding it too decadent and indulgent and choose to continue worshipping Merrshaulk anyway, even though he doesn't actually answer prayers.

Set

Set
Alignment	3E: Lawful Evil 5E: Chaotic Evil
Divine Rank	Intermediate God
Pantheon	Yuan-ti, Mulhorandi, Egyptian
Portfolio	Deserts, Disease, Drought, Darkness, Betrayal, Ambition, Murder
Domains	3E: Air, Darkness, Evil, Hatred, Law, Magic, Scalykind 5E: Death, Tempest, Trickery
Home Plane	Great Wheel: Ankhwugaht (Baator) World Tree: Ankhwugaht (Heliopolis) Phaeronic: Twelve Hours of Night
Worshippers	Yuan-ti, Lycanthropes, Egyptians, Thieves, Assassins, Wizards
Favoured Weapon	The Spear of Darkness (Spear)

"Bitches for Thulsa Doom!"

Just like his predecessor, Sseth also became bored and sleepy, although he still granted spells even in his dreaming state. That was up until the Time of Troubles in the realms, where all of the gods were kicked out of their respective realms and forced to the mortal world until one of them owned up to stealing the tablets of fate from Ao.

During this time, the winged avatar of Sseth decided to go for another nap, but was captured by a mighty Sarrukh priest known as Pil'it'ith and imprisoned. Allowing his cult to be subsumed by another evil god of snakes called Set, who now grants all spells in Sseth's place, even though the Yuan-ti have no idea that the switch actually occurred.

Set; is the jealous personification of evil, and being a "human" deity obviously has far more followers than Sseth, and therefore more widespread appeal. This means that Set was likely to have more of a meaningful impact on the world than the successive serpent deities were managing to cobble together. He also has the added bonus of not following that trap of getting tired when sacrifices aren't being given, although presumably, he's extremely happy to receive the bloody offerings whenever they're given.

Sseth still sleeps, hidden somewhere in the multiverse. His extent of contact with the outside world is an increasing number of disturbing visions being granted to his former followers in their dreams, though most of them don't have a clue what they're all about, other than getting a sense that their god is in trouble. The reasonable course of action is to perform more drastic rituals to empower their god, which unknowingly only empowers his captor.

Because his portfolio has been usurped, it is likely that he won't last for very long, because gods thrive on the power of prayer and faith, so Sseth is likely getting starved to death. Those Yuan-ti that have the power and inclination to do anything about it simply don't know where to look, smarter Yuan-ti realize that their power and ability to look is being granted from a new source that probably doesn't want them looking in the first place.

While this largely applies mostly to the Forgotten Realms versions of Set and Sseth, later editions split them back apart again. After the 4E Spellplague Mulhorand was completely wiped from the map and Ao kicked out the pantheon, leaving nothing but mortal descendants of the old deities. Shortly after this Pil'it'ith' and his heretic followers were killed in a Yuan-Ti uprising, leaving the floor for Sseth to return to prominence as Set faded from memory.

5e

In 5e, he's back, and seemingly, at least sseth's older Merrshaulk aspect, is locked in a sort of magical sleep that prevents him from personally intervening in the usurpation of his power, but some Yuan-ti has caught on to this, and have begun to seek a means of restoring him properly. Mulhorand pantheon also returned during the second sundering, but it's unknown to what capacity Set still has control over the Yuan-ti and their imprisoned gods.

Worshippers

Being the primary deity of the Yuan-ti, Merrshaulk/Sseth/Set is obviously worshipped most strongly by Serpentfolk in general.

The whole thing about sacrificing living beings is considered a foregone conclusion in Yuan-ti society. Willing Serpentfolk are considered the most desirable to their god, and those who freely give themselves over to be sacrificed are treated like royalty for three days before the event, being denied nothing whether it be food, drugs, sex or even a simple demand for someone to give you their house for an afternoon. Non-Serpentfolk races are just lined up and get their hearts cut out.

Clerics of Sseth (and maybe Merrshaulk) get their divine calling directly from their deity, receiving a vision in their dreams. This means that there are little to no denominations of the church, since they all receive their instruction from the same source. It also means that you can't fake being a priest of the cult or turn your back on your faith, because all other priests can be told as soon as it happens.

Yuan-ti Cultist

The main prestige class for servants of Merrshaulk can be found in Savage Species, and unlike the watered down classes that the subsequent incarnations of the deity get (see below) the Yuan-ti Cultist is pretty awesome.

Firstly, they continue their divine spellcasting progression as normal and gain access to the bonus Suffering domain granting them new spells and a -2 STR & DEX debug with a touch.

They can also spit poison, do the Moses thing of turning sticks into snakes, and earn psionic powers that can cause increasing damage to enemy targets subject to Will saves, culminating in a Save vs Death (and take 6d6 damage if they pass).

The best bit about the class is the increasing induction into the inner circles of Merrshaulk's cult, which steadily improves the Cultist's social modifiers with other Yuan-ti, but also allows them to evolve into more powerful forms. Early on they learn a ritual to turn Purebloods into Half-bloods, and later learn another ritual for turning Half-bloods into Abominations Eventually, they also become Outsiders as they become the "Voice of Merrshaulk", which also comes with Spell Resistance, Telepathic communication and the ability to Dominate other Yuan-ti.

Fangs of Sseth

A prestige class from Serpent Kingdoms which is essentially a Yuan-ti assassin. The are divine Assassins who live by a simple code which overrules any other orders handed down from priests: Do not harm other fangs of Sseth.

Beyond that, they act as spies and Assassins for Yuan-ti communities. They gain resistance to poisons, improved sneak attack damage, spider climb at will and oddly improved range BAB (but not melee). Their one cool feature is a divine vision from Sseth at level 8, which gives them a buff, making them utterly undetectable for 8 hours.

The class is actually pretty sucky, requiring you to waste some feats by taking mediocre ones just to qualify. Having only a 2+INT skill points per level progression. Any class features gained would probably be overtaken by a normal Assassin and it's coolest feature is a one time only deal.

Glorious Servitor (of Set)

Set's unique prestige class from Lost Empires of Faerun has nothing to do with snakes at all. It also requires Improved Turning and 2nd Level Divine casting as a prerequisite, but has nothing to do with them either

Instead, the Glorious Servitor prestige class let's you turn into a monstrous scorpion at level 1, then gives you increasing buffs as you progress, such as +6 AC and +3 STR while in animal form, and also giving Spell Resistance, Poison Immunity and eventual transformation into an Outsider. Despite the bizarre entry requirements, This class at least has an attempt to theme, but competes against a Druid for the shapeshifting party role. But is stuck with one form and no spell progression.

Realm

Merrshaulk's realm is the 74th layer of the Abyss called Smargard which is an endlessly vertical jungle full of disease, acid rain and poison. It is believed that the layer actually has no floor and just goes all the way down.

Set's realm of Ankhwugaht is located in a dark portion of the Egyptian group of planes called Heliopolis. Ankhwugaht itself is sited in the Baatorian layer of Stygia Set's realm is a poisonous desert of snakes and scorpions, where the communities are populated by mummified slaves and lich advisors. Necromancy spells cast in Ankhwugaht are Empowered and Extended.

Ravenloft Set

Set
Alignment	Lawful Evil
Divine Rank	Unknown
Pantheon	Ravenloft
Portfolio	Deceit, destruction, drought, storms
Domains	Curse, Death, Evil, Trickery
Home Plane	Unknown
Worshippers	Akiri
Favoured Weapon	Shortsword

In Ravenloft, Set is one of the three most significant deities worshipped in the Amber Wastes cluster. His clerics go around, masquerading as clerics of other gods and try to subvert and corrupt their faiths from the inside.

In Gothic Earth, the RPGA module Cycle of the Hunter explicitly states that Set does not exist in the setting, even as the name for a demon/devil, even though cultists to him (and presumably historical Egyptian lore) do. A curious exception given all the other horrible creatures that exist on Gothic Earth.