Slayers

Slayers are mutated humans who have undergone magical transformation, typically at an early age, enhancing some of their natural defenses against magic and common monster-abilities. They are part of the Source Lands Setting, and are inspired by "Witchers" from "The Witcher" universe, by Andrzej Sapkowski, but also more directly inspired by the Blood Hunter Character Class from D&D Beyond.

Biology
See Source Land Species for information regarding the Slayer Species, which is primarily used to symbolize someone who has been successfully mutated into a Slayer.

Mechanics
See the D&D 5e Homebrew Classes for information regarding the Monster Hunter class, which is primarily used to symbolize someone with Slayer Training.

History
Slayers were created by the Elves, who needed new protectors against the many dangerous monsters of Terra, as their own magical abilities began to dwindle and the mechanical defenses of the Eldar had long since ceased to function.

First Attempts
Initially, humans were used by elves, to fight their enemies, so they themselves did not have to. Humans, unfortunately, lacked the Elven Resistance to magical corruption, and sending humans to deal with monsters and magical threats resulted in more monsters instead of fewer - some claim that the Elves inadvertently began the first Goblinoid Wars by sending humans to fight magical creatures.

Survivors
However, some humans returned - victorious, but ultimately forever changed by the battles they had endured. These humans had mutated due to magical corruption, a phenomenon Elves later discovered a cure for, though at the time, it proved beneficial.

Studies into Mutation
It proved to be the same mutation that would turn humans into monsters that had, in some cases, turned them into harmless, or even superior mutants, that were now, largely, immune to the magical corruption, and thus better suited to fight monsters - the elves began to study the corruption and the mutations to see if there were ways to replicate the beneficial mutations, but avoid the harmful ones, and eventually had some breakthroughs.

Proto-Slayers
When the first Slayers were formed into a fighting unit, they operated as large teams that exterminated monsters, learning and building the craft as they went, but apart from some minor beneficial mutations, they were largely just humans who had developed a very high tolerance to magical corruption, though eventually, as the years passed on by, the Elves perfected the craft and the true Slayers came to be - and so the Elves scattered about Vaults in which humans could be turned into Slayers,preferably at a young age to ensure success, and most of these vaults remain functional until the very end of the Colonial Era.

Imperial Slayers
As the Empire rose, they preserved the Slayer Orders, who had remained neutral during the conflict with the Elves where humans freed themselves. As a result, the Imperial Edict did not grant Slayers or Mutants a citizenship - as they also treated half-elves and elves as second-rate citizens, but they did quickly find themselves needing the Slayers and came to certain arrangements with the slayers.

The Orders
The different Vaults all came to be associated with their own Orders and as the years passed by, the Orders grew to have nothing more than a distant kinship that sometimes dissolved into rivalries, which occurred around the same time the nations of the Westerlands experienced much the same transformation.

Golden Age
The brief Golden Age of the Slayers came about in the wake of the Post-Imperial Era, during which the chaos that ensued from the various nations claiming more independence and the government decentralizing considerably, saw an increased need for Slayers, who largely operated as Journeymen.

The Decline of the Slayer Orders
As the Colonial Era came about, the nations of the Westerlands were irrevocably turning their backs on their Imperial Past, with almost no exceptions, and the Slayer Orders remained conservative and archaic element that shackled the traditions of the land to the past. Replacing the Slayer Orders were Source Companies, that were basically just willingly mutated humans, undergoing a simple mutations that largely prevented Source Corruption, and magic users working together to try to do what these ancient orders had done for millennia.

The End of the Slayers
Nearing the end of the Colonial Era, only a few Slayers still remained active - considered the highest experts and authorities on monster killing, the general population had come to think of Source Hunters and Slayers as being one and a the same, which also applied to the Monster Hunters themselves. People briefly spoke of the "return of the slayers" when some wizards had successfully managed to mutate humans in fashions that largely mimicked the old way of making Slayers - however, this emphasized how the Slayers had truly been forgotten even more, as people had come to think of the mutations, and not the traditions or training, as what made a Slayer.

Orders
The different Slayer Orders specialized in different monsters, native to the regions they themselves prowled, and had specific hallmarks that separated them from each other.

Order of the Dragon
The Order of the Dragon predates any of the other Orders - not because their Slayer Vault is older, but because the other Slayers had not properly organized themselves at the time when the Order of the Dragon became an organization. It is the original Imperial Order, which specialized primarily in slaying or capturing young wyrms. They were instrumental in forming the Imperial Dragon Knights, who rode lesser wyrms into battle - though both the Order of the Dragon and the Imperial Dragon Knights are largely things of a forgotten past when other Slayer Orders begin to properly surface.

Vault
The Imperial Vault is somewhere in Estheim, in an undisclosed location - however, the Order of the Dragon predates all other Orders, and as such, many of the original members came from other vaults.

Traditions
The Order of the Dragon's traditions are largely unknown - at least past the point where any other Orders came about, as the Order does not leave Imperial Heart-Lands, except if to act as advisors to Imperial Emissaries, on how to conduct themselves around other Slayers or matters of monsters - however, the traditions of the Order of the Dragon as they were prior to the separation of the Orders is still known to most Slayers.
 * Fighting Style - The Order of the Dragon were known to train as Hoplites, using spears and shield with relatively light armor - however, few slayers have chosen to copy this style, citing that it was likely so because this was the only reasonably well developed fighting style at the time, and argue that in reality, the Order of the Dragon probably used a wealth of other tactics and specially crafted weapons.
 * Game Mechanic - It is unknown exactly how the Order of the Dragon would be represented mechanically.

The Order of the Gryphon
The Order of the Gryphon is based in Orlais, specifically in Dussante. They were among the first Orders to fall when they became inconvenient for the Orlesian Crown, but were also one of the most prominent orders - and among the only to have ever taken sides in politics, and as a direct result, perhaps the most famous of the Slayer Orders among common folk through the history of the Westerlands.

Vault
Located somewhere in Dussante.

Traditions
The Order of the Gryphon's traditions always remained very Dussantean, with their Order being known for the tendencies toward seeking glory and fame, more so than rewards. Adrenaline junkies and dare-devils, who live on the praise of the bards and the common folks and would consider it a much greater reward to have a feast thrown in their honor than to have their purses filled with gold.
 * Fighting Style - The Order of the Gryphon followed which ever fighting trends were common in the Dussantean Courts, putting no particular stock on the importance of a symbolic fighting style, as Monsters had to be slain with guile and cunning regardless. During most of the Post-Imperial Era, they practiced mainly sword and shield, though toward the end, they omitted the shield more often and favored a longer sword only to finally adopt sabers.
 * Game Mechanic - The Order of the Gryphon would use the "Monster Hunter" martial archetype from the Fighter Class in 5th Edition D&D.

The Order of the Manticore
The only known Neferan Order, the Order of the Manticore is a non-Westerland Order and was a mirror of the Order of the Dragon, but operates with greater freedom than their Imperial Counterpart, but it is said that this Order has its own sub-chapters, not very different from how the Order of the Dragon more or less shattered into multiple other Orders.

Vault
The location of the Manticore Order's Vault is entirely unknown to Westerlanders.

Traditions
The traditions of the Manticore Order are not well known, but most Westerland Slayers who have met these foreign co-workers, claim that they were willing to extend an occupational courtesy and appeared competent and not too different from any other Slayer School.
 * Fighting Style - No consistent reports exist.
 * Game Mechanic - It is unknown exactly how the Order of the Manticore would be represented mechanically.

The Order of the Sphinx
The Order of the Sphinx is the only surviving Rahamran Order, that exists past the beginning of the Post-Imperial Era, but actually has roots in the Order of the Manticore, as the founding members were originally Neferan Slayers, however, they supposedly use the first Slayer Vault that the Order of the Dragon used, before they captured a new one in a more convenient location, and as a result, the Order is frequently known as the "Free Guild", or the Order of the Lion, because few people outside of the Rahamran Nobility are familiar with what a Sphinx is.

Vault
Their Vault is located in Mosul, one of the Free Cities of the Northern Rahamra,

Traditions
The Order of the Sphinx is known for conducting themselves as Assassins and Mercenaries when work is slow, giving them a shady reputation - however, fully legal, as there is a massive loop-hole in the laws of the Free Cities, dating back to the original agreements made by the Empire thousands of years ago, that the Order adamantly adheres to - namely that Slayers are not considered humans, and no more than a Donkey or a chicken, can human law be applied to them - this naturally can't function, but it seems an informal agreement has been worked out, where the Order agrees to not completely ignore the law, but continues to take shady work quite openly.
 * Fighting Style - The Order uses poison to kill their enemies, monsters or humans, and as such, they favor swift and accurate weapons as well as ranged weapons. Their school, however, teaches traditional Shamshir fencing and various forms of archery.
 * Game Mechanic - The Order of the Sphinx uses the Assassin Roguish Archetype, as the Order has largely become more of an Assassin's Guild that just also accepts contracts to assassinate monsters, more so than a Slayer Order that also occasionally kills people.

The Order of the Wolf
Known commonly as "The Nordmarian Order", the Order of the Wolf is different from other Slayer Orders because they lack a traditional vault. The Nordmarians somehow made their own vault, which produces a similar result, but ultimately is very different.

Vault
The Nordmarian Vault is located somewhere in the Northern Isles of Nordmar, overseen by the Ravna Tribe, and holds religious importance to the Nordmarians.

Traditions
The Nordmarian Slayers are well accepted by Nordmarian Society, but are also known to be more traditionalist and following a confusing set of traditions that are somewhat alien and absurd to those standing outside of Nordmarian Culture. There is, in fact, no Nordmarian "Order", per say, rather informally, other Slayers have come to refer to the Nordmarian Slayers as the "Order of the Wolf" due to the unique nature of their mutations, and with the absence of an actual Order, it is a mystery how the Nordmarians have maintained their Slayer Traditions for so long.
 * Fighting Style - The Order has no preferred Fighting Style, as there is no school associated with the Order or the Vault.
 * Game Mechanic - The Order of the Wolf uses the Order of the Lycan from the Blood Hunter Class.

The Witchhammer
Fire is fought with Fire. So are Witches. The Witchhammer is an Order of Slayers that is part of the Cosmonite Church's Inquisition against unsanctioned Magic Users, and the members of the Order are known for being magic users themselves.

Vault
The Vault is found in the Noverran Capital, and is part of a giant monastery complex.

Traditions
The Witchhammer is a religious order that hunts down Source Corruption and those who spread it and spare no collateral damage in their efforts to safeguard the realm against the viles of magic.
 * Fighting Style - The Order uses magic to fight magic, but seeing as most of their enemies are human magic users, their primary weapons are crossbows and warhammers - both very effective against ordinary people.
 * Game Mechanic - The Witchhammer uses the Order of the Profane Soul from the Blood Hunter Class, and typically take the following feats - Warcaster and Mage Slayer.
 * Sister Order - The Silver Hand hunts Lycanthropes, and is viewed with great hostility by Nordmarians and has often feuded with the Order of the Wolf.

The Last Rite
In the early Colonial Era, the Carnalan Government decided that the Carnalan Slayer Vault was the property of the Carnala Republics, and sold it to wizard who wished to change the Slayer Order, however, due to an outcry from the Mortician's Order (a Carnalan Mage Guild), which in turn caused mass panic, the Last Rite survived and was granted the right to also use the Vault - prior to the rise of the Carnalan Slayer's Guild, which threatened to replace the Last Rite, without usurping their function and specialties, the Last Rite was best known for hunting the Undead, and rooting out illegal necromancers.

Vault
Prior to the formation of the Carnalan Slayer's Guild, the Last Rite were the sole owners of the Carnalan Vault, found somewhere in the Carnala Republics, but they now share it. Uniquely, this is the only vault to have ever been created by humans, and was not merely captured or inherited from the elves.

Traditions
The Last Rite always functioned more like Police Officers, mainly acting on grievances filed by, or against, the Mortician's Order, who can largely be credited as being the reason why the Last Rite came to exist. One could not safely exist without the other, and, while in only small number, this is also why the Last Rite continued to exist until the very end of the Colonial Era.
 * Fighting Style - The Order primarily fights the Undead, which means they utilize a broad number of fighting styles adapted specifically to the many different kinds of undead - however, for academical fencing, the Last Rite used Rapiers for most of their existence.
 * Game Mechanic - The Last Rite uses the Ghost Hunter Order from the Blood Hunter Class.
 * Sister Order - The Dawn Guard is a Sister Organization that views The Last Rite as their parent order, specializing in Vampires, though this Sister Order recruits from far and wide.

The Night Wardens
The Night Wardens is the Mark Land Order, and was established by the Order of the Dragon, being the first other Order to ever exist, having been formed to travel out into the countryside and hunt down monsters, as the Order of the Dragon primarily specialized in Wyrms.

Vault
The Vault is somewhere in the Marklands at a secret location.

Traditions
The Night Wardens is known to people as "Watchers" or the "The Night Wardens", because their original name was Natt'Wachtern, which is an archaic term, from when the Imperial Language was still, basically a butchered combination of Dwarven and Elven, meaning Warden of the Night. Long since "Wachtern" ceased to mean Warden, the word remained solely associated with the Order, and people came to call the members of the Order "Wachtern", which is now considered a rather sophisticated way of addressing any slayer, indicated a higher education. The Night Wardens largely created the overlapping tradition of how Slayers would travel around as Journeymen, offering their services for coin and bounties, and is the largest of the Orders, and well respected by all other Orders.
 * Fighting Style - Influenced by the Orlesian Guild, the Night Wardens adapted a formal academical fighting style, being that of the Long Sword, though before they did so, one could argue that their primary fighting style was the short-sword, as this is considered every Warden's fall-back weapon.
 * Game Mechanic - The Wardens use the Order of the Mutant from the Blood Hunter Class.
 * Sister Orders - The Talanthian Order is not so much a sister order, but rather a foreign chapter. They branded themselves as traditionalists, and use the Short Sword, the Short-Spear and shields as their primary weapons, leaning toward the Order of the Dragon in inspiration. The Carnalan Slayer's Guild is also largely a sister order of the Night Wardens, being modeled on them.
 * Other Traditions - The Wardens forego their personal names and utilize archaic Imperial Names, making them very recognizable.