Questions such as this one and this one cover how to execute horror in a role-playing game fairly thoroughly. This process must be modified, however, when the traditional trappings of a game session are twisted.

As previously described in this question I asked, I am in the planning stage of a 3 GM, ~20 person mega-game that will take an entire weekend to play. Horror is entirely about setting a mood, which is difficult enough to do in a confined space with four players. How can a group of GMs effectively provide the horror atmosphere to a large group of players who have the ability to roam wherever they choose?

To extrapolate on the type of game: We are using Call of Cthulhu and Delta Green as a base for the mechanics. The players are divided unevenly into three different groupings. The smallest group has the most resources at their disposal, the largest has the least. The groups, while ultimately should be on the same "side" (i.e. humanity), will have opposing objectives and information.

The game takes place in a fictitious city. Each GM is responsible for one section of the city. Whenever a character moves from one section to another, the player follows suit and moves to the part of the house where that GM is stationed.

Each section seems to gravitate toward one type of horror: dread (fear of the unknown), terror (fear of the known), or gore (repulsion by the unnatural). So advice on any and all of these types of horror is welcome. If I had to be pressed to pick one overarching theme, however, it would be dread.

Good answers should draw on experience of running horror scenarios in general, running large-scale games in general, or preferably having run a large-scale horror game.

  • 1
    \$\begingroup\$ Please give us more information about the kind(s) of horror you wish the campaign to evoke. Although great horror moves between different varieties, most stories have one main theme: advice will be very different depending on whether the story focuses primarily on dread (fear of the unknown), terror (fear of the known), or gore (repulsion by the unnatural). \$\endgroup\$
    – BESW
    Apr 29, 2015 at 22:31
  • \$\begingroup\$ @BESW would it be problematic for the question if I said "Yes"? \$\endgroup\$
    – sillyputty
    Apr 29, 2015 at 22:34
  • \$\begingroup\$ It just means answerers will have to work harder. Which isn't a bad thing, if their efforts are useful to you. You might want to add a little bit saying that you're interested in different sorts of horror though, to telegraph that's the kind of answer you need. \$\endgroup\$
    – BESW
    Apr 29, 2015 at 22:36
  • 4
    \$\begingroup\$ Please, please, please, write an after action report on the game. I, for one, would be really interested in hearing how it went. \$\endgroup\$ Apr 30, 2015 at 6:38
  • 1
    \$\begingroup\$ @Sardathrion We're planning on filming it. \$\endgroup\$
    – sillyputty
    Apr 30, 2015 at 12:47

2 Answers 2


True horror requires player buy in, characters with powerful motivations, a willingness to be less than powerful, and a willingness to make the wrong choices for drama. All it takes is one computational demonologist or heroic soldier and all the "bad decisions" go out the window in favour of "let's shoot the big green monster until it stops making us crazy."

So, the most critical aspect here is PC design with malice aforethought. Determine what aspect of dramatic horror you wish to evoke (you may be able to achieve a single tone, maybe), and hit that note as hard as you can in character design, set design, and encounter design. Obviously, some tonal variation will be necessary to provide a plot and pacing, but as a group endeavour to have a single tonal theme. Much of horror requires an intentional pacing and protagonist-coerced involvement (i.e. the protagonists of the story just can't say "nope, sorry. Busy.") with players able to go "nope, busy" and able to vote with their feet to a different room, it'll be very hard to maintain the appropriate horrific tension.

I would recommend having a theme of horror, without the tone of horror. In a 20 player game, your primary source of drama will be the players working at cross purposes. Fight that at your peril. Instead, enable that tension with character motifs and motivations that may nod (or result in) various horror tropes or tones. Then any actual horror evoked is the fault of players interacting with each other. Make sure that players are given plenty of -detcord- rope to hang themsleves with. Make evil accessible, seductive, and give the appearance of being easily mastered with no nasty consequences whatsoever, then let players trip each other up.

As you have three factions, at least one of whom has quite useful familiarity with these horrific creatures, you have different "breakpoints" of horror, even presuming the PCs are fully immersed in character (which I would find absurdly difficult to believe in a 20 player game of whatever stripe.) Familiarity breeds contempt, and what are residual human resources for one are "oh no! the dead are walking! run!" for another (and requiring a quiet talking to by HR for using "terms pejorative to the vitally challenged.")

To sum up: you have too many players, too many possibilities for divergent timing, too many options for player freedom to decline to be horrified, and too many levels of competence: aim for supernatural adventures with horrific tropes instead.

  • \$\begingroup\$ There is just so much good in this answer... Thank you. \$\endgroup\$ Apr 30, 2015 at 6:41
  • \$\begingroup\$ We've done one game like this before, based on the Aliens movie franchise, where there was a true atmosphere of suspense for the players. So we know it CAN be done, we're just looking for better ways to do it. \$\endgroup\$
    – sillyputty
    Apr 30, 2015 at 12:48
  • \$\begingroup\$ With this size of group, the original question, and your answer, Brian, it makes me think of The Walking Dead, only abstracted a layer away from the main group of the story. Yes, there's a horrible and horrific backdrop to the story overall, but the story is really about the character interactions, and the tough choices they have to make to survive in a damned world. \$\endgroup\$
    – Aviose
    Apr 30, 2015 at 14:56

Safety in numbers only applies if you can trust the others

Are you familiar with the game Werewolves of Millers Hollow? If not; it's basically a game you play with 10-20 people. Each person is either a citizen or a werewolf. The game is divided in "night" where people close their eyes and the werewolves secretly pick a victim who leaves the game and a day-phase where everyone (including the bad guys) bicker and argue and then together pick another person to leave the game. Despite being played with 20 people, you don't get that feeling of "safety in numbers" at any time, because you don't know who is on your side. It becomes a game of "you versus the world, and some of them can turn into monsters and eat you".

If you play the game with the cards open, it would not be scary, nor exciting, nor a challenge. But because you play with the cards closed and can't trust people, it suddenly becomes challening and the entire feeling of being "a group of citizens fighting the werewolves" is gone completely. Even though you are a group in the end.

Play with hidden objectives and alliances

So I guess the way to make play dreadful is if you hide everyone's objectives and alliances. At the start of the game, give every player a secret briefing which contains hidden information on their faction, their objectives, etc. Make sure that it's clear to everyone that not everything is as it seems. Make sure that briefings are full of lies, too. Remember that not everything you know is true; just because you think that character X is secretly an evil cultist doesn't mean he is. But the fact that you think he is, will change how you play, which will change how character X plays (because he's not trusted, but he knows he's a good guy, so you must be secretly plotting against him, right?

Make sure some of the factions are not immediately obvious. (This can be a player who is an evil cultist, but it can also be a citizen who is an undercover Majestic operative, it can even be a citizen who just really hates a specific person in another team and wants them dead)

Optionally you can give these briefings out randomly to take away any idea of GM favoritism.

Breed mistrust

Include a side-room where people can get away from the others to discuss things in private. This will immediatly make others distrustful of whatever goes on in there, even it's just tea and biscuits. Occasionally, as a GM, ask players to join you. You can either give them secret info or just ask them if they're having fun. Whatever you do, when they come back out, everyone will be suspicious. Nobody will believe that the GM just took you aside to ask you if you were enjoying the game.

Make sure that information becomes available from time to time that shows the players they really can't trust anyone and they are absolutely right to keep their motivations hidden.

Force players to pick people to trust, even if they can't

Once everyone is suitable suspicious, make sure the game has opportunities where you cannot help but trust others to help you. At some point, you'll probably have to go in guns-ablazing and shoot some cosmic horror. But if you have to divide 5 rifles under 10 people and you know at least 2 of them will shoot you in the back at the most inopportune moment, you'll get a lot more anxious about the whole experience.

Pick a horror that is relatebly human and preferably played by one (or more) of the players

If the horrible being you have to fight is a cosmic green alien who breathes fire but exists only because the DM tells you about him, it's hard to be scared. If the cosmic horror is instead a skinwalking demon who leaps from body to body, devouring the soul from the inside before moving on to his next victim, and he's currently occupying the body of what was once Jim, and you just told Jack and Tina that you trust Jim and they should take him along on their trip, and you realise this just after they've left for the off-side room and you can't follow them, and you don't know if they'll come back out, and if they do, whether they'll still be themselves, that's quite something else.

It also means at some point that you might have to kill one of your friends' characters because you think he's a demon. But you might be wrong. But if you hesitate, he'll be on to you. Or you might have to hide your suspicions, but he was just trying to convince another character to check someting out with him, and you're pretty sure that other character is on your side....

Giving the players hard choices, and letting them experience the consequences of those choices, will go a long way in setting an atmosphere for a game. Shooting an NPC just means the DM won't talk about them anymore. Shooting another PC means someone will be out of the game. And he'll probably have a few words to say, especially if you were wrong, and player get the option of a good death-scenes before they are gone.

Recruit the dead to improve the atmosphere.

Since it's no fun to be out of the game, make sure you have roles for the dead. Creepy ones. For example, if you kill another player, but he turns out to be innocent, turn them into a ghost. Let them follow the person who killed them around and whisper things to them for the rest of the game. Imagine having "You don't trust him? You didn't trust me either. You killed me. Look how well that turned out. Do you really think this murder will go over better?" whispered into your ear by the person you killed while you are contemplating killing someone.

Likewise, you can recruit dead players who were not so innocent into more creepy roles; whether as crazed sources of information, rerisen as undead or demons, or just as sources of a haunting who can sit near a GM and suggest terrible things to happen from time to time.

Watch this review of a Megagame in action

I've played many games of Millers Hollow, which aren't entirely roleplaying but definately work with the aura of mistrust. But what you're doing is a step more extreme. But nothing extreme hasn't been done before... so I'll link you this video.


It's by the people from Shutup and Sit Down, a boardgame review. In it, they play a game created by a group called the Megagame Makers. It has about 50 players and the scenario is that each group of 4 players plays a country on earth, the scenario is the arrival of alien forces (also played by a group of players).

It's mindblowingly awesome, a good video, and shows how a game like you're planning to do might go. While it's not classical horror, I think it will definately help you, if only with the logistical requirements of a game on the scale you are planning.

If you don't want to watch the whole video, the (surprising) outcome is under the spoiler:

In the end, it turns out the aliens are friendly. They had been claiming this for the entire game. This did not, at any point, stop the various countries from mistrusting each other and nearly unleashing world world three, stealing and sabotaging each other's progress, and sending the world's population into complete panic over a looming alien threat.

If you want more info on the guys who make these megagames and some of their rulesets and stuff, check out their site: http://megagame-makers.org.uk/

  • \$\begingroup\$ Great tips. I've seen the SUSD video before, and we've run one other mega-game before as well. Definitely good advice here on how to amp up the suspense and dread. \$\endgroup\$
    – sillyputty
    Apr 30, 2015 at 12:43
  • \$\begingroup\$ So much amazing in this answer. It's hard to choose a better answer between this one and Brian's as to which is better to me. I am glad that @sillyputty has to decide and not me. He has his work cut out for him. It makes me want to run a game like this, and I haven't run a game with more than 6 players in about 10 years. \$\endgroup\$
    – Aviose
    Apr 30, 2015 at 15:08
  • \$\begingroup\$ In our previous large-scale game, when a character died we had NPCs for them to take over and turn into PCs. The suggestion of having different roles for dead players is a good one as well. \$\endgroup\$
    – sillyputty
    Apr 30, 2015 at 16:57

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