These events occurred a couple months ago already, in an ongoing 4e game I'm DM'ing, set in an indeterminate campaign world. Time flies by so quickly!
Here's my party: an Unaligned Shaman, an Unaligned Rogue, an Unaligned Invoker of Erathis, and a Good Paladin of Avandra. Of my players, 2 I've known/played with for a decade, and the other two are fairly new to me (but are both proving to be excellent additions to the group). The two new players are running the religious characters.
The setup: the party arrives at Grebenheim, a trading town run by a council of merchants. They discover that the town's Citizens all seem very happy and are pursuing various higher callings; none of them do any menial work, which is left to the Workers. Eventually (they almost missed this, by virtue not asking), they learn that the Workers aren't living slaves, but are zombies. Every citizen is bound by an Oath, agreeing to allow their remains to be put to work. This interests the shaman (a student of cultures), intrigues the invoker (spread civilization on the backs of the undead? Why not?), and angers the paladin (undead are evil, and evil is bad!).
As they have done the town a service, they are able to get a tour of the zombie "factory." Clutching their weapons and wary of ambush, they go. Kenneth, one of the mid-level technicians (with a Canadian accent), walks them through. No dread necromancers here - it's an assembly-line setup, culminating in an artifact of a long-fallen civilization. No BBG, just some skilled tradesmen performing their specific tasks.
The paladin is all for destroying the place...in a few levels. There are a lot of Workers, after all, and good can wait, right?
Enter the mysterious NPC. He tells a tale of souls enslaved, imprisoned in their own rotting bodies with just enough will left to carry out their orders, but damned to remember everything. He tells of tens of thousands of Workers tucked away in "long term storage," where unsightly damage and irreparable rot doesn't have to be looked at. He tells of his five year old sister, dead and animated, sent back to her old house to clean the chimneys. And, eventually, he tells of his own time as a Worker, before a falling rock from a demolition project destroyed part of his skull, and the control device implanted therein. And then he tells them that they could free all the trapped souls, if they could just deactivate and destroy the proper equipment in the control room.
Cue Paladin Rage.
So, after some debate, the party sets forth, and seizes the control room. Some mistakes happen, leading to the death (rather than the subdual) of the two guards on duty. Some Arcane checks are made, and some aren't - the characters figure out how to disable the control devices, and to sever the connection between the control devices and the trapped souls, and to destroy the control mechanisms (but don't want to break the 50 foot tall magic crystal, for fear of catastrophe). They don't learn, until a little too late, that severing the souls from the bodies doesn't deanimate the bodies; this leads to tens of thousands of uncontrolled zombies turned loose. They also manage to kill the two control room technicians by tossing them down a 50 foot drop without checking the length of the fall first.
So, in two sessions, we've gone from a civilized trade center, to a scene out of a George Romero flick, and the characters are feeling a little tarnished.
Did I go too far?
The original concept was simply "how can I learn more about these characters, and especially these new players?" From that, I went to "what if the underlying religious tenets of these two characters were a little conflicted?" And from there, I hope you can all agree, the step to "Zombie Apocalypse!" is an obvious one. It also fits nicely into my overarching campaign, which involves outside forces intentionally increasing chaos and entropy in stable societies. But it started feeling a little bit grim last night....