Before my reflections get totally out of hand, here’s something delightful for you.
I have very conflicted feelings about this template. See, the whole Warhammer Empire concept (my inspiration in this case) is designed to justify a Neo-Nazi worldview. Knowledge, open-mindedness, and embracing of diversity are cardinal sins that will bring the end of the world as you know it. So basically, what I believe in personally is antithetical to the concept of the witch hunter (and a setting specifically designed so that everybody has ample reason to fight everyone else.)
In my D&D setting, characters made treaties with goblin tribes, allied with stone giants, and brokered peace with a marsh full of monsters. Not so in Warhammer; what is wise in one game is suicidal in another.
Warhammer glorifies ignorant violence by making the dilemma one-sided. There are actual demons that will gush into the world through a weak-minded psychic or magic sensitive, regardless of their intentions or choices. You do unthinkable things to those who may or may not be innocent, because if you hesitate or show mercy, the world is destroyed.
Chaos is everywhere. Humanity is not strong enough to resist with military might or force of religion. Tolerance is the key to failure; only by rigorous hunting of the Chaos at work within and beyond human civilization by those strong enough to act is there a chance of not being swept off the map as the landscape itself is tortured into the fever dreams of aliens shaped by the darkest imaginings of humanity.
Also, there is a powerful allure to playing jack-booted thugs that are extensions of a powerful and corrupt authoritarian system. The Men in Black, the Federal Agents, the ones with a license to kill, those who can commandeer local forces or spit in the eye of the rich and powerful. You may be the baron, but I say the word, and you get strapped to a stake and burned to death. And we can confiscate your lands. So STFU.
I’ve had one lengthy campaign that coalesced around those traveling with a witch hunter because of the motive for adventuring, the sheer authority, and the endless supply of evils to subdue. The anti-hero tradition is built on the idea that while you may not be the good guy, you suppress evils far worse than yourself. This sums up the witch hunter nicely.
There is a certain moral relief to knowing that if you must do distasteful things, you do them out of necessity; the weakness is in doubt and hesitation, not in ignorant ethnocentrism or punishing the innocent for your risk aversion or protecting the privileged status of those on power from the marginalized.
In Warhammer, no matter the innocence of the shell, Chaos lurks everywhere. It’s not just about ideas; the fear that bigots and the privileged feel is actualized into a hostile magical power to fight. Those who are different from you really do spell the end of the world if they are not stopped.
So yeah, this is me squirming a bit as I even make this template. However, there are a few points to consider in the World Between.
For one, there is no Chaos in this setting. It is true that the World Below consorts with all kinds of deal-makers and power-mongers that could certainly use some hunting down, but the pervasive and one-sided demonic energy of Chaos (with no balancing power) is not the flavor of the World Between. There are other choices in many cases, and the innocent need not always be destroyed.
For another, this is Gothic fantasy. To do it properly, we must have the fear of the World Below gaping always hungry. We must have a focus on the fragility of individual salvation. We must have a desperation for purity when confronted with temptation. We need a Church frantic to maintain its authority and wealth while also trying to hold on to its theology and discipleship, where the two poles form something of a spectrum that has shifted painfully towards worldly concerns as an institution even as it forms individuals who are forceful believers.
In an atmosphere of pervasive corruption and desperation at every level, the purifiers emerge as a proposed solution that often intensifies the problems.
The Church of the Lady of the White Way is theologically determined that only the Lady is worthy of worship, and all other gods are basically powerful aliens or demons or spirits, below the Lady in stature. In this setting, that’s a belief and a culture–but is it the objective truth? Is the world better for cutting off all supernatural interaction save that with the Lady? Is that even possible? The question there is much less clear-cut than “Chaos will eat the world om nom nom.” Purifiers are doing what they think is right–but that doesn’t mean they ARE right, not like in Warhammer.
As a final note, while all these templates are playable, I also create them with the DM in mind. These make fantastic NPCs. Whether they need help dealing with an infestation of evil, or whether they suspect the PCs of corruption, they are tough and hard and they often roll around with a pack of back-up just in case.
Jack Shear introduced witch hunters in the World Between here.