Create Tension and Drama in Horror RPG Combat

Combat in tabletop role-playing games often evokes  tactical manoeuvres and calculated decisions on hexagonal grids populated with figurines. While this may be common in Dungeons and Dragons or Shadowrun, I believe horror RPGs must take a different approach. In horror, combat is not a test of "character build" or tactical skill—it’s an eruption of chaos and violence that heightens tension and immerses players in the story’s dread.

Achieving this requires more than just deadly mechanics. Combat must be grounded, emotionally charged, with transparent mechanics that easily translate into fiction, and capable of occasionally generating unexpected results, while mostly conforming to expectations of fictional outcome. Based on my experience as a GM and insights from systems like Call of Cthulhu, Delta Green, Vaesen, Trail of Cthulhu, Fear Itself,  this post explores how to strike that balance and optimize combat for horror RPGs.

These are certainly not the only systems I played horror games with: World of Darkness, Chronicles of Darkness, Savage Worlds, GURPS Horror, and Kult, all have their strengths and weaknesses.

Why Combat Matters in Horror RPGs

In horror RPGs, combat serves a different purpose than in other genres. Rather than being a tactical puzzle, it’s a narrative tool that reinforces the themes of vulnerability and desperation. Combat should:

• Feel uncommon and impactful, not routine.
• Be quick and lethal, reflecting the fragility of the characters.
• Heighten tension, making every decision and roll feel significant.

When done well, combat becomes a moment of catharsis or terror, an explosion of violence that leaves players on edge. Systems like Call of Cthulhu, Delta Green  excel at this by delivering fast, lethal mechanics. Systems like Trail of Cthulhu and Fear Itself (based on the Gumshoe framework) require in my opinion some adjustments to achieve similar results, but have the advantage of of often expediting resolution even more.

Transparancy of Mechanics towards Fiction

For combat in horror RPGs to feel immersive and engaging, there must be a clear and immediate relationship between mechanics and narrative fiction. Players should be able to:

1. Easily Interpret Their Actions in terms of Mechanics: When a player describes an action—such as firing a gun, diving for cover, or grappling an enemy—the mechanics should clearly and intuitively reflect the described action. This avoids breaking the immersion to consider rules and mechanical details and keeps the game moving smoothly.
2. Translate Rolls Back into Fiction: After a roll is resolved, the results should be clear to interpret in terms of the fiction. The effect of rolling the dice and immediately knowing whether the result is good or bad, increases the tension associated with the role. In contrary, an ambiguous result, a "success at a cost" muddles the waters and reduces the impact. Also, whether it’s a hit, miss, or critical failure,  the mechanics should provide enough guidance to craft a compelling description.

In summary, the mechanics should be transparent towards the fiction. It should be possible for the players to decide their actions without much consideration of the quirks of the system, and there should be immediacy to interpretation and resolution of the outcome. This is one of the reasons why I believe that many "narrative" systems, like, for instances 10 Candles or Dread, are not as capable of exploring drama from combat. The mechanics are just too dissociated from the fiction.

Moreover, partial successes and successes at a cost are also problematic, if (as in PbtAs) they require that after the roll one makes a decision about the outcome, breaking immersion, and moving the player from emotion to reasoning; giving them a choice on the outcome is quite contrary to the feeling of helplessness that roots a horror game.   

By maintaining a strong connection between mechanics and narrative, you ensure that players remain immersed in the fiction even as they engage with the rules. It also helps reinforce the tension of every action, as players can see the immediate stakes and consequences of their decisions.

The Importance of Tension Before Rolling the Dice

One of the hallmarks of an effective horror RPG is ensuring that players feel the tension before they roll the dice. 

Systems like Call of Cthulhu and Delta Green excel at this because their mechanics give players a clear understanding of their odds. Knowing that they have, say, a 30% chance of success or a 5% chance of catastrophic failure allows players to anticipate the stakes, making the moment of the roll genuinely nerve-wracking.

In Trail of Cthulhu, on the other hand, the odds are clear, but the player can manipulate them before rolling by spending ability points. This can reduce considerably the tension, at least until the characters start running out of points to spend.

In Vaesen, or CoD, or WoD, the dice pool system makes it harder for players to estimate their chances of success. This can reduce the emotional build-up before a roll, as players are less able to weigh their odds. To address this, GMs can take an active role in framing the stakes:

• Clearly explain the probabilities of success based on the number of dice being rolled;
• Suggest the potential consequences of success or failure before the roll. ("If you fail this roll, it could be really very bad for your character.")

By making the stakes clear and palpable, even systems with less intuitive mechanics can deliver tension-filled moments before the dice hit the table.

Balancing Predictability and Swinginess in Horror RPG Combat

To create memorable combat encounters in horror RPGs, it’s important to maintain a balance between predictable mechanics and occasional swingy moments. This swingy moments up the tension considerably. 

Consider this: would you prefer to attack with a 50% chance of success or with a 70% chance of success but a 5% risk of a critical failure that could result in your character’s death? Critical successes and failures make each roll feel significant, even if 90% of the time the outcomes themselves are relatively low in impact.

Here’s how I see it working where it works well. I call it the 10% rule:

1. Predictable Outcomes (90%): What normally happens when you try an action, such as, if you shoot your gun you hit and do some moderate damage or fail. When you dodge, you either avoid damage completely or take moderate damage.
2. Swingy Outcomes (10%): About 1 in 10 rolls should result in a critical success or failure, introducing unexpected chaos. This mirrors the randomness of life-and-death situations in horror, and it increases immensely the tension before each roll.

In Call of Cthulhu and Delta Green, this balance is achieved naturally through percentile dice and possible critical success/failure outcomes (1/10 rolls on average will result in extreme/critical success or failure). 

In Vaesen, or other dice pool systems, the dice pool creates a different type of tension, where players must contend with the uncertainty of success and the impact of multiple successes. However, Vaesen in particular misses rules for critical failure, and several successes are necessary for real added impact, resulting in a low probability of extreme outcomes. In my experience, it is noticeable that this dampens the immediacy of combat.

For Trail of Cthulhu and Fear Itself, house rules like adding critical success/failure mechanics or increasing weapon lethality can help. Some versions of Gumshoe, like Swords of the Serpentine, do include a critical success mechanic that can easily be ported to Trail and Fear Itself.

Moreover, combat should be fast and lethal. In systems where combats tend not to be like that, you can either add house rules to increase damage or, even simpler, design opponents that can cause considerable while being themselves relatively frail (also known as glass cannons).

Immersive Combat Descriptions: Moving Away from Tactical Maps

One of the most effective ways to heighten immersion and drama in horror combat is through how you describe the scene. Exact overhead maps with grids tend to focus players on tactics, turning combat into a chess match where characters feel like pawns. This perspective undermines the emotional immediacy that horror demands.

Instead, provide players with a rough, quickly scribbled diagram that conveys the basic layout of the battlefield and the positions of the combatants. This looser approach shifts their focus away from exact measurements and tactical optimisation, encouraging them to think from their character’s perspective.

To further enhance immersion, describe the situation from the point of view of each player’s character at the start of their turn. Paint a vivid (but brief and functional) picture of what their character sees and hears:

• "The rotted floor beneath you creaks as you step back. You grip the pistol in your hand. Five meters to your left, your friend Paul just smashed the head of a zombie that jumped him with an axe.";
• "The cultist in front of you is getting ready to attack you again with his knife. From the corner of your eye, on the right, you glimpse the inhuman monstrosity moving slowly from the shadows towards you, growling. On your left side is Sandra, who just shot her revolver past you, at the creature, and is swearing while recharging."

This doesn't require any mechanical adaptation, so it is possible to do with any system. However, systems that depend too much on exact distances of movements and attacks will make it more difficult.

Summary: Practical Tips for Horror RPG Combat

To summarise, the following advice can help you improve Horror RPG Combat:

1. Introduce Critical Outcomes: the system should (or be adapted to) ensure roughly 10% of rolls result in critical successes or failures.
2. Amplify Lethality: If combat feels very flat and long, consider increasing the damage per attack to make every decision feel high-stakes.
3. Clarify Probabilities: help players understand their chances to heighten tension before rolls.
4. Strive for Mechanical Transparency: As much as the system allows, try to keep the fictional interpretation of the mechanics and the mechanical interpretation of the fiction intuitive and transparent.
5. Focus on Perspective: Use vivid, first-person descriptions and rough diagrams to enhance immersion and reinforce the characters' viewpoints.