As I reminded myself in my last post, my tagline is "d20 rules, Call of Cthullhu paradigm." The only reason I didn't use D&D rules is because I've focused my efforts on d20 Modern, but realistically, d20 Modern uses the D&D rules too, after all. It's not a really significant change to the "engine" of the system.
It's been a while since I talked specifically about how to incorporate that "Call of Cthulhu" paradigm to the D&D rules. I've blogged a bit here and there about how to limit power and magic, but that's only one part of the whole. Coincidentally, I found myself thumbing through my copy of Darkness & Dread, a Legends & Lore series entry from Fantasy Flight Games written by Mike Mearls back in 2004. I bought it when it was still fairly new, read through it, and then haven't looked at it much again. Much of this is because what it offered I already have solutions for in other formats. And the GMing advice, which was reasonably nice, paled next to the GMing advice by John Tynes in the d20 Call of Cthulhu game itself. But, like I said, I was recently re-reading it, and because it's focus is specifically on modifying D&D to provide a dark fantasy or horror fantasy approach, I found that it was fun to refresh my memory on it. In particular, I think its organization is well done, and making a "checklist" on how things work in a horror d20 game led me to believe that I might actually have left out a hole or two that needs patching. So let me get to it: what things do you need to do to make D&D (or another d20 game, like d20 Modern in my case) work as a horror fantasy game?
Something needs to be done about characters; specifically the classes that they can pick. D&D characters are designed to be heroic, competent, and basically to "win". From a flavor perspective, some of them don't fit into a dark fantasy tone either, because they're basically superheroes. My solution to this was to leave the D&D classes behind. By using the d20 Modern/Past approach with the "Shadow Stalkers" campaign model, I have characters who are arguably fairly swash-bucklery and competent (for their level) but who are also designed specifically for a low-magic, grimmer and grittier approach that's best suited for a horror game.
Horror House Rules
Mearls gives several optional house rules at this point. He calls them optional templates that can be added to the game much as templates are added to monsters to change their attributes. Here's my approach and/or thoughts to each. Again; I actually don't necessarily prefer the options in the this book, but having some kind of option, or some reason specifically to eschew the option, is a good idea if a horror tone is desired.
Death spiral. Mearls also introduces a death spiral mechanic; you know, one of those mechanics where when you take damage you actually become less effective in combat (which means you're more likely to take more damage, then become even less effective, and then take more damage... etc. until you're dead or the other PCs manage to save your bacon. Hence the name.) While I agree that such a rule does indeed mimic some horror gaming tropes, and makes combat much more scary to get into, I find death spiral effects are more tedious than anything else. I avoid them. No thanks, Mike.
Fear checks. My madness rules include a fear mechanic, but I actually quite like Mearls' Fear check, and his rules for determining the "fear check DC" for any creature in the game is quite handy. The only problem I have with the Fear checks listed here are that they are based on Will saves. This means that tough, burly warrior types are more likely to be afraid than bookish scholars, since warrior types tend to have poor Will save and nerdier types do not. I'd prefer to borrow the modified level check from resisting an attempt to Intimidate (as per the skill) instead. Not because I like the proliferation of a rule that's basically a Will save but not, but because the Will save doesn't quite render the "proper" results. This works quite well in a situation in which you don't have Madness or Sanity rules of some kind, or in which your Madness/Sanity rules don't have any Fear effect.
Madness. The Madness rules in Darkness & Dread are too complex. They feel like the overly complex and clinical Sanity mechanics from Cthulhu. I greatly prefer the simplified, yet similar in result, Madness rules that came out in the d20 Freeport book. Freeport is, after all, pretty much a Lovecraftian dark fantasy setting in its own right, at least in the mind of its creator.
Research and Investigation
Mearls makes the sensible point that in a horror game, combat is often secondary to good research; if the characters can figure out some weakness or vulnerability of the horrible supernatural monstrosity, that's a much better strategy then confronting it in open combat anyway. He makes a few suggestions on how to facilitate this with the d20 rules.
Knowledge skills collapse. The various Knowledge skills end up becoming somewhat esoteric. He recommends collapsing them all to a single Knowledge skill, and making types of knowledge have a DC based on category. While this is a nice idea, for Knowledge skills that get little to no use in a typical D&D game, they do get more use in a d20 Modern game, plus it gives the Smart Hero something to spend all those crazy skill points on. While this isn't at all a bad idea, and I'd use it for a D&D base, I don't need it for d20 Modern/Past. He also suggest revising Knowledge to let it work more like the Research skill in d20 Modern--naturally, I don't need to do that if I'm already playing d20 Modern.
Tomes. This quintessentially Lovecraftian element is added, pretty much exactly the same way that it is in the Cthulhu book itself. I've already got a few; I really should come up with some more. But I can also borrow titles from Lovecraftiana anyway.
Libraries. Again, this is the Research skill from d20 Modern. Although new to D&D in 2004 when Mearls wrote this book, it is pretty much exactly the same as an existing mechanic in the other d20 games already.
Mearls rightly points out that magic in a horror game is different than magic in a high fantasy game. Here, he still has regular D&D magic (I don't) although it's reduced, and adds an element of "darkness" to some of the spells. In DARK•HERITAGE you can plausibly claim that all magic is black magic. This is an idea that I took from the Cthulhu game; I actually think that the d20 Cthulhu game handles magic better than the BRP game. Plus, it's more compatible with other d20 games, so I can adopt it as is much easier.
Turns out I don't need to, because Incantations with their cost and backlash are pretty much equivalent to Cthulhu spells already. So I just use them, although sample Incantations are pretty thin on the ground in the books that have them. I need to probably manually make up some more to have in my hip pocket for later on when I need them.
Pacts and Corruption. Mearls has infernal pacts with evil outsiders--Faustian bargains, quite literally. This is a really nifty mechanic that I should borrow in my game. I had kind of forgotten that it was in this book. He also has Corruption as a mechanic tied to pacts. I think his corruption is a little bit muddled, though. Plus, I kind of like the Taint mechanic from Unearthed Arcana instead--which I believe was borrowed from Oriental Adventures where it originally appeared. It somehow seems just a bit meatier.
Forbidden Magic. Rather than classify some SRD spells as "forbidden" as opposed to others, by making almost all of my magic come via Incantations, it all takes on the aspect of being forbidden, dangerous, and somewhat insane to use. I've got this one well covered.
Mearls believes that D&D monsters are too familiar to D&D players to serve in a horror game. I'm actually going to reverse the order of the two sub-headings here, just because I think it's easier to talk about them this way.
Monster familiarity and customization. I actually disagree with Mearls on this one. I don't think he's wrong exactly, but I think that you have to be careful and deliberate in how you use monsters to make them work in a horror setting. After all, actual horror games tend to use very familiar monsters--to the point of over-use. Lovecraftian tentacled entities are almost like "comfort food" in horror gaming by now, and vampires still get plenty of traction. It's not a question of using or not using familiar monsters, it's a question of how they're used. But I've blogged about that before, so I won't get into it too much again in this particular post. But his rules for customizing and "reskinning" monsters are nice.
Abominations and godlings. Abominations are basically home-made monsters of frightening mien. In this case, it felt like a brusque re-telling of the monster creation rules which we already have in pretty robust form in plenty of d20 games including D&D and d20 Modern both. And godlings are monsters that don't even have stats--because basically you don't fight them in the traditional sense. They're more like specialized hazards that need to be addressed first via research, to find their weaknesses, and then via other checks that banish them, or otherwise cause them to go impotent--if you're lucky, and naturally after a tense encounter.
I think that advice on both is fine. The godling paradigm in particular is useful. But I've got plenty of monsters. I've probably got more monsters than I have any other rules element--mostly because I like monster books and I have quite a few of them. Many of them are beyond the scope of being beat in fair combat in an E6 game, especially one with sharply reduced access to magic relative to D&D normal. So rather than create my own, why not just pick one of the many, many monsters I've already got, reskin it flavor-wise if needed, but otherwise use as is?
The last two chapters of Darkness & Dread I'm not going to get into, because they are more about adventure construction, and a sample mini-setting, and this particular post is about mechanics. But again, I found if nothing else that the organization of this book was very helpful. And skimming through it and reading some of its sections again, I was reminded that I may not really be covering all of the facets of making d20 play like it's got a Call of Cthulhu paradigm after all; I'll probably officially incorporate pacts and taint into my rules set.