I've been thinking a lot about magic and gods and things you need for a home-brewed setting. I've got the big things in place, actually for many years, but it's the smaller bits that connect, or give flesh to those ideas that give a world life. Or at least make it internally consistent.
One of the key Gods is the God of Death. Guardian of the veil between life and that that is beyond. Key themes or powers are welcoming souls at the end of their natural life, providing healing for those whose time has not come, hating the undead with vengeance, and comforting those who are near to the end of life.
The usual trope for an RPG Death God is one seeking souls, domination and looking to turn the world into an Undead Paradise. Or at least Lawful Neutral. My concept is more like a gatekeeper, easing the passage of souls in one direction and fighting against any attempt to cross back again. And it was human once, but a very long time ago.
Now the Gods deal in metaphysical conflicts beyond the keen of mankind, so it's up to the worshippers of each God to do their bit. The Death Worshippers tend to set up hospitals in poorer areas and root out any rumours of necromancy. But as they are the only sect that has powers to heal and cure diseases, ailments, injuries and other misfortunes, they are rather popular amongst the common folk. Most of this healing is a good understanding of hygiene and disease and infection vectors, and herbcraft, administered by the general clergy. But even these worshippers, at least the devout and experienced ones, can tell when a life is near its end, and where it is likely to be cut short. It's more like the infection is too advanced or the immune system is too weak than a limit on one's days.
So the Death Church (don't have a catchy name yet) mainly organises what passes for medieval hospitals, focussing on poorer areas but present in all towns and cities, but also provides healing and care to important folks as well for political support and extra funding and favours. Either way, they are rather popular amongst the common folk and ruling class.
Those worshippers that have talents of the magical type are both valued and thrust into the most dangerous situations - subtlety is not the Churches style. Most will learn true magical healing, which is beyond the simple wound healing and brewing of healing potions that mages and alchemists can perform. This can remove infectious diseases from a body, cure PTSD, knit bones and muscles in an instant, and cure other serious injuries. However, they draw some of the injury or disease into themselves, and must overcome that through their own strength. Also, the centre of epidemics or battles is not a safe place to set up a triage centre.
Others of a different magical bent are trained as Agents to take the fight to root out the Undead, They pretty much have all the spells and powers of your RPG necromancer but use it to resist, destroy and banish those creatures created by necromancy. It's curious, as either demons, buried evils, or necromancers are the ones that create mindless undead, and they are using the same magical powers to create the undead as the Agents are to destroy them.
These Agents are trained in at least the basics of combat, and supported in their efforts by a larger number of Initiate Warriors, trained to use silver weapons and well versed in tactics and weaknesses of the Undead. Grouped in strike teams, they usually guard those temples or hospitals that may be threatened, but can strike known or suspected necromantic targets.
Those that have appeared in play have been focussed and scarily efficient, but also somewhat fatalistic ("When it is my time to die, I will die then...") and a great boon to players taking on Undead forces.