Pennetra (New Combat System)

 

Okay, here’s a new combat system.  I’m calling it Pennetra because I had to write the word ‘Penetrating’ like 10 times in this post and other potential names like Penetrox are already taken by industrial aluminum joint compounds.

I’m trying to do (1) something new, and (2) something where a smaller % of attacks are misses.

Simple Version

This is the one-roll version.

Next to each weapon in your inventory, you have two numbers: Penetration and Damage.  Penetration helps you hit, and Damage is how much you hurt the other guy.  

	Penetration	Damage
Dagger	d4	4
Sword	d6	4
Greataxe	d6	5

Making an Attack

When you make an attack, you roll Penetration to see if you hit.

• If the result equals the target’s Defense, you hit.

• If the result is 2x the target’s Defense, you hit 2x and deal +2 damage.

• If the result is 3x the target’s Defense, you hit 3x and deal +4 damage.

That’s it.  That’s the whole mechanic.

Modifiers

• Increase your Penetration die by 1 size if you are a Fighter.

• Increase your Penetration die by 1 size if you have a magic weapon.

• Increase damage by 1 point if you are strong.

• If you have a situational bonus to hit, decrease their Defense by 1 point.

Defense

Unarmored = 1 (everything hits)

Leather = 2

Chain = 3

Plate = 4

Dragon = 5

There’s a satisfying effect here: against unarmored enemies, all weapons are equally likely to hit.  However, against heavily armored enemies, daggers (and other small weapons) become almost useless.  (The big advantage of daggers is that they can be concealed, thrown, and used in a grapple.)

When you get a situational bonus, you decrease their Defense instead of upgrading your Penetration die.  This is to benefit small weapons (like daggers) and non-fighters.  If you have a situational advantage against a person in leather armor, a dagger is as good as a sword–which kinda makes sense.

Some side effects of this system:

• Attacks hit more often, so you’ll need to increase HP if you want combat to take a similar number of rounds.  Alternatively, keep HP the same if you want combat to be shorter than what you’re used to.  (For monsters, I’m going to try 5 HP per level and see how that feels.)

• Physical weapons got a buff, but magic didn’t.  As a result, magic damage will feel weaker than what you might be used to.  This might actually be a feature if you want to push your wizard players towards using non-damaging spells.  It might be a bug if you want your wizard to be the nuke.

• The scaling between armor types is sharper here.  Plate is stronger than what you are used to, and leather is much weaker.  Chain is about the same.

Adding Complexity: Double Dice

Okay, maybe you want something a little more interesting?  Let’s change it to a pair of dice rolls.

	Penetration	Damage Die
Dagger	d4	d6
Sword	d6	d6
Greataxe	d6	d8

Once rolled, these dice are not fixed.  You can switch them freely.

This makes it even easier to hit your targets now.  It might look like you’ll be doing a little less damage, but since you can arrange your dice so that (if both dice are equal-or-higher-than the target’s Defense) the bigger die is the damage die, that doesn’t end up being the case.

The modifiers are the same as above.  2x and 3x hits each add another d4 of damage.

Monster Attacks

Some speculative conversions.

	Penetration	Damage Die	Flat Damage
Goblin	d6	d4	3
Bandit	d6	d6	4
Bear	2 x d6	d8	4
Orc	d8	d8	5
Ogre	d10	d10	6
Owlbear	3 x d6	d8	5
Giant	d12	d12	7
Dragon	3 x d10	d8	5

Adding Complexity: Mighty Maneuvers

Fighters have a chance to do cool things with their attacks, for free.

Beginning at level 2, Fighters get a third die to roll, called the Mighty Maneuver die.  This is a d4 at level 2, but it becomes a d6 at level 4.  (If you have a d5, you can use that for level 3.)

The fighter will roll all 3 dice, and assign each one to a task: Penetration, Damage, and the Mighty Maneuver.  After damage is dealt, the value showing on the Mighty Maneuver die becomes the DC for the enemy’s save to avoid the Fighter’s combat maneuver.  You still need to hit your target in order to attempt a Mighty Maneuver.

Enemies usually use a d6 to resist, or a d8 if they’re good at it.  And a lot of actions are impossible.  (You’ll never shove a dragon, for example.)

Example:

Frollo the Fighter attacks, and therefore rolls all three dice: 4, 5, 6.  The target has a defense of 3 (chain).  He decides to use the 4 for Penetration (a hit!) and the 5 for damage.  The 6 becomes Frollo’s trip attempt.

His enemy, the evil unicorn Hexodia, is not easily tripped with four legs.  The unicorn rolls a d8 to avoid being tripped, but gets a 5.  This is less than Frollo’s 6, and so the unicorn topples with a surprised neigh.

Alternatively, Frollo could have used 6 for Penetration (a double hit!) and 1d4+4 for damage.  (The extra 1d4 comes from the second hit).  This would have left the 5 for the Maneuver.  Since the unicorn also rolled a 5, it would not have been tripped.

Why Would Anyone Use This System?

Compared to regular D&D, there's less math and smaller numbers, so attacking is a little simpler. Attack rolls are probably faster for everyone except the fighter. And attacks miss less often, so combat feels faster.

Compared to Into the Odd, it allows for smoother scaling of enemy difficulty. In ItO, enemy Armor affects your hit chance and reduces your damage (effectively double-dipping). In Pennetra, enemy Defense mostly reduces your chance to hit, but because you often switch dice to land the hit, the hits tend to be smaller as well, so Defense functions as a subtle (and milder) form of damage reduction.

It has diminishing returns on strong attackers, which is nice. Even if you get your Penetration die up to d12 (or d20), you'll still miss occasionally against an armored foe.

I think it preserves the intended differences between the different weapon types, while still giving people a reason to carry a dagger.

And it makes Fighters feel cool. They get something that no one else does.

Discussion

You could take this a step further, and add a fourth die that improves your Defense for the next round.  There’s a couple of ways to do this, but I don’t like any of them very much.  

I probably would let a player take a total defense action, though, and gain +1 Defense at the cost of forfeiting all other actions.

Expect some hesitation as players try to figure out which configuration does the most damage.  (It’s not too hard.  An extra hit is worth 2.5 points of damage.)  Is this decision interesting and meaningful?  Maybe.

It’s more interesting for fighters, since they have to choose between dealing more damage and doing something cool.  It could potentially lead to some situations where a fighter focuses more on the maneuver and less on the damage, which is cool.  

I like fighters to be: 

• Simpler than other classes.

• More spontaneous.  Instead of declaring what spell you are casting, a fighter is largely reacting to openings that the enemies give.

• Good at doing several things in combat, not just damage.

Domain Expansion

Actually, you could rip out the engine from Pennetra and apply it to other types of resolution mechanics. Example: crafting.

When you craft something, roll a Materials die, Tools die, and a Skill die. The results are assigned to your three goals of Quality, Efficiency, and Time. (Low Efficiency means that you end up using more raw materials than you thought you would. High efficiency means that you have some left over.)

If you think of any other fun applications, post it in the comments.

Some Classes

GLOG-adjacent.  Fighters and barbarians are both durable, but they’re different kinds of durable.

Fighters 

Fighters upgrade their Penetration die by 1 step.

Level 1 - Defend

Level 2 - Mighty Maneuvers 1d4

Level 3 - Extra Attacks

Level 4 - Mighty Maneuvers 1d6

Defend

Once per round, you can intercept a physical attack that was meant for an adjacent ally.  You take all of the damage that they would have taken.  You can declare this after damage is rolled.

Mighty Maneuvers

See above.

Extra Attacks

When fighting multiple enemies, a Fighter can attack two enemies at once.  They will roll all three dice at the same time.  A Penetration die is assigned separately to each enemy, and the third die is used for Damage.

Alternatively, the third die can be used for a Mighty Maneuver, performed against both enemies simultaneously.

Barbarians

Barbarians get more HP than fighters, but they can’t wear armor.  Like Fighters, they also upgrade their Penetration die by 1 step.

Level 1 - Rage

Level 2 - Quaff

Level 3 - Mighty Strength

Level 4 - Mighty Rage

Rage

Increase your damage die by 1 step, but you cannot take any actions that aren’t part of an action to directly murder your enemies.  Rage ends when all enemies are subdued or driven off.  Once per round, you can attempt to end it early with a 2-in-6 chance of success.

Quaff

You drink down some booze.  It heals for you for 1d6+[Level] HP, but you get drunk.  For the next hour, if you ever (1) make an attack roll (2) and miss (3) and get doubles, you suffer a fumble.  Your weapon breaks, an enemy gets a free attack against you, etc.

Mighty Strength

You can do some magnificent feat of strength 1/day, like rip a door off its hinges.  If used to intimidate, you get a large bonus.  This ability isn’t useable in combat.

Mighty Rage

Your rage improves, increasing your damage die by another step when raging.

Monster Checklist

Okay, so you’re writing up a monster entry.  Run through this checklist to make sure that you haven’t missed anything.

#1. The concept should be unique, compelling, and communicable.

You probably have a lot of concepts in your head, but which ones make for good monsters?

You want something that is different from what your players have already encountered (unique), you want it to be cool enough to hold their attention (compelling), and you want it to be something that you can describe (communicable).

Like, a lot of Lovecraftian monster concepts will fulfill the first two requirements, but if you can’t describe how it looks and fights, it’ll just be a blob of hit points to your players.  (Minis assist with, but don’t negate, this requirement.)

It may also be worthwhile to think about the monster will be described by you at the table (and by other DMs).  The best monsters are the ones that can be conceptualized in a single sentence, even though you can spend additional sentences embroidering it.

Lub Glubs from Adventure Time
(They look like drifting pool floaties until they get close.)

#2. The monster must be fun to fight.

We’re talking about monsters, so combat is likely to be involved.  Your monster must be fun to fight.  This comes from (2a) abilities, but also (2b) tactics, (2c) environment, and (2d) weaknesses.  Each of these is worth a fuller discussion, so I’ll talk about them in their own sections below.

So let’s return to talking about the things that make combat fun.  Abilities, tactics, environment, and weaknesses.

#2a: Abilities should be appropriate, novel, and dynamic.

By ‘appropriate’, I just mean that the mechanical representation should match the fiction.  At a basic level, fire breath should do fire damage, but does a ghost hammer deal bludgeoning or force damage?  What’s the best way to handle a lich that drains your life?  Level drain, Con damage, reducing max HP, exhaustion, or reducing hit dice?

You have a lot of leeway here, so get creative.  Players appreciate when a mechanic is especially cutely appropriate, but it’s not a requirement.

By ‘novel’ I mean that you should try to give them something that they haven’t seen before.  If you’re writing an adventure, you need to make sure that there is good differentiation between your concepts.  (If you’re writing a monster manual, you can have some similar monsters, because it’s not like the DM is going to make the players fight all 7 dragon varieties in a row.)

And by ‘dynamic’, I just mean that the abilities should push players into interesting decisions.  Fire breath is cool and threatening, but it’s not dynamic.  The players just take the damage and keep on trucking–there’s no choices to make.  Wall of Fire is more dynamic, because now the party is split and they have to make interesting choices about whether or not to jump through the wall of fire, or wait for it to dissipate.

#2b: Tactics should also be appropriate, novel, and dynamic.

You don’t need cool abilities to have a cool encounter.  I wrote a post about how tactics can make for fun differentiation between mechanically identical monsters.  I won’t rehash it here, except to say that different monsters in your dungeon should have different motivations for opposing you (food?  defense?), different roles within combat (hit and run? blind aggression?), different combat goals (eat you?  rob you?  escape?), and different levels of commitment to combat (morale).

Simple things like modes of movement and attack can also suggest interesting tactics.  For example, a flying skeleton archer doesn’t need any special abilities, because you already know that the players will have to come up with new tactics to defeat them (compared to fighting regular skeletons).

#2c: Environment should also be appropriate, dynamic, and/or interactive.

You could argue that this belongs in the adventure design section instead of the monster design section, but the two are interrelated.  Combat should never take place in a featureless white room, and certain monsters are more likely to be found in certain locations.

The environment for flying skeleton archers might be a lonely clifftop where sky burials were practiced.  Or it might be an ancient bridge where the bird cult threw sacrifices off.  Or it might be deep in the catacombs, with bone “nests” built high up on the walls.

Interactivity comes from hazards and difficult terrain, but it also comes from advantages.  Cover, chokepoints, hiding places.  Also explore verticality: stairs, levels, half-levels, ladders, pits, steep slopes (“scrambles”) and pools.

Also consider how the environment affects an encounter.  A low roof makes a flying skeleton archer much easier to defeat.  Conversely, if the room has a high ceiling and is bisected by a pit, flying skeleton archers are much more threatening.

#2d: Every monster needs weaknesses (either implied or explicit).

If none of the monsters have any weaknesses, the players will use the same offensive tactics to kill them every time.  This can be implicit, like how a flying enemy is “weak” to ranged attacks and nets, or how a stupid enemy can be baited into a trap.

Or a weakness can be explicit, like scarecrows being weak to fire.  I’m not a big fan of hard lock weaknesses that require a specific material or spell.  “Immune to damage from non-silver weapons” or “Possession can only be ended by casting protection from evil”.  If the party has a silver dagger there’s no interesting decision to make–you just use the dagger.  And if the party doesn’t have a silver dagger, they just run away and there is again no interesting choice to make.  (Hard locks like this can sometimes be useful as metroidvania-style keys, where a certain monster is impassible until the party can come back with silver weapons, but that’s still a weaker use case, in my book.)

I prefer soft lock weaknesses.  “This enemy takes double damage from silver weapons” or “possession can be ended by protection from evil, holy water, or unconsciousness”.

Best are versatile weaknesses, that allow players the most flexibility in how they are approached.  “This monster’s brain is exposed, and it takes triple damage when attacked from above” or “100% food motivated” or “scared of loud noises” or “killed by falls”.  However, you’re a little more limited in these, since you have to use options that all parties have access to, so you shouldn’t only use versatile weaknesses–you should have some soft lock weaknesses in there, too.

Also remember that weaknesses can take the form of buffs to the party.  A flying monster with a ranged attack is pretty threatening but if it gives everyone within 50’ the ability to fly, it provokes a new set of tactics and risks.  Similarly a monster that is blind and has a terrible sense of smell allows for players to effectively “turn invisible” when they’re fighting it, which also allows for new and interesting tactics.

#2e: Consider threats besides "it kills you". Consider solutions besides "you kill it".

Murder is a common language in tabletop. A fight to the death is instantly interesting, and it is a common focus of game mechanics. But please, step outside of that box.

I talked about alternative types of threats up in #5, but also consider that the players might "win" the combat through other victory conditions:

• Prevent the monsters from fleeing and raising the alarm.
• Avoid breaking the priceless vases in this room while the monsters try to kill you.
• The monster is a sage.  Every round, you can ask a question that the left head will answer truthfully.  Meanwhile the right head (and the rest of the monster) is trying to kill you.  Stay alive and think of good questions.
• The monster is treasure, but only if you kill it in a specific way.

This is also why we have monsters with specific weaknesses--to force players away from their regular tactics.

• This monster can only be killed by silver (or salt, or fire, or song, or whatever).
• The monster cannot be killed while it is in contact with the earth.
• This monster can only be drowned.
• This monster will only die if it is physical removed from its tomb.
• This monster cannot be harmed by anything crafted by the hands of men.

Usually, you want to tell the players the weakness early on, and then let them figure out the best way to solve the problem.  If you want to throw your players at a monster without letting them know how to kill it, at least let them escape easily.

#3.  The monster should support interesting dungeoncrawling.

If you haven’t played an OSR game, you might be used to having combat start once the players walk into the room.  But there’s a huge potential for interesting (hostile or non-hostile) interactions to occur before initiative is rolled.

This includes things like roleplaying and faction play.  But it also includes things like:

• Bone needle men prevent all rest in a dungeon.  The party could hunt them down and silence their rattling skulls.

• Goblins have tiny crawl tunnels they use to move between rooms.  The party could block them off, or strip off their armor and crawl through themselves.

• Through the keyhole, you can see an owlbear sleeping.  Ferocious, but known to be easily distracted by a large enough piece of meat.

This is where you can get really creative, and where the most interesting OSR-style problems can be inserted.  However, these sorts of things are usually buried in the monster write up.  The rattling of the bone needle men is probably obvious to a reader since it’s listed under monster abilities.  But the crawl tunnels of goblins might only get a brief mention under the Ecology section, where it’s easily missed.  And while the monster entry might mention the rapacious hungers of owlbears, that type of interesting situation is often missed by the monster manual, and left for the people who write adventures.  (Which is a pity.)

This one is probably the hardest to address, since it doesn’t map well to any of the normal sections of a monster entry.  Still, you should give it some thought.  A monster has the potential to be a lot more than a stack of hit points and abilities.

Some places where a monster could interfere with dungeoncrawling:

• It's a member of a larger faction.
• It blocks off part of the dungeon.  Optional: it's probably big enough to TPK the party.  Optional: it has a weakness, discovered elsewhere in the dungeon.  (Basically just a lock and key.)
• Literal lock and key: once it is killed (or appeased) a new path unlocks.  The water level falls.  The necropolis opens.  
• It interferes with a resource:
• Light
• Rest (e.g. no resting or eating lunch)
• Healing (e.g. all healing is halved)
• Magic
• Loot (e.g. the treasure is cursed until you kill the mummy)
• Senses (e.g. no noise is possible in the Halls of Silence)
• It burrows between the rooms, creating new tunnels.
• It has an easy line of communication and/or observation, and can speak to the party as they navigate the dungeon.  It may want to scare them away, want the party to release it, etc.
• It can generate illusions.
• Curse of the Dao: all fall damage is doubled.  (And the monsters know this.)

#4. The monster should fit into the world.

The monster needs to fit into the world in a way that makes sense.  This usually gets glossed over–if you are designing another undead then everyone already knows that it was created by a necromancer, or arose spontaneously from some sort of restless spirit. If it's alive, you should spend a second to think about where it eats, sleeps, and hunts.

But maybe your design is something more novel.  Your monster is the angry anti-ghost of the unborn.  Or maybe something that is too specific for the DM to just drop it in the dungeon without an explanation, like a squad of humans who fight with grenades.  In those cases, you need to spend some time explaining the context for this monster.  

It’s tricky because you may be torn between providing a specific explanation (“These are Malthusian grenadiers, servants of Witch Mountain.”) or a general one (“Grenadiers are commonly employed by mercenary forces.”)  Because we want our written words to sound authoritative, we often just pick one–but of course there’s nothing stopping you from giving 2 or 3 contexts that your monster might exist within the game world.

Also, consider giving your monster actionable connections to the world. A mated pair of owlbears should imply valuable babies nearby. The presence of the dandelion knight is proof of an alliance with the fairy princes (so the party should be extra wary of them). This vampire has the sword of St. Vipera--is this the Saint herself?

Even something small like a group of orcs, where one incongruent orc is wearing a brand new set of armor, raises interesting questions (and connections) with a single detail.

#5 - The monster should be threatening.

Sure, your monster has attack rolls and it deals damage.  It certainly poses a threat to HP totals.

Attacking HP is the oldest and most comfortable way to threaten the players.  It’s also the one that is always approved by the implied social contract of the table.  (Players don’t object if they take 17 points of damage.  But depending on the game, they might object if their sword gets rusted away since it feels unfair.)

The mnemonic for this is “attack all parts of the character sheet”.  Abilities scores are usually fair game.  Inventory is usually a possible target, too, except in very protective 5e games.  XP/Level Drain is an option, but can be deployed with care.  Character abilities and skills are usually off-limits, but you can still tamper with them in ways that are fun.  In 5e you can have monster abilities that attack inspiration, hit dice healing, proficiency, ideals, etc.

But also remember that you can attack the out-of-combat resources, too.  Time is a big one.  Noise can attract wandering monsters.  A monster like a carbuncle might have a valuable gem on its back that goes down in value after each round of combat.  Killing these (murderous, frenzied) dwarves might ruin your reputation with the (friendly, chill) dwarves in the next cave.

Threat is one of the biggest ways that a monster can engage your players, so think about it carefully.

#6. The monster should surprise.

I’ve touched on this before, but you want your encounter to be dynamic.  It should force the players to change their plans a little bit.  

Ideally, you want to push the players into at least three interesting decisions.

A simple example of this might be:

1. There’s a giant golem in the next room.  How do we kill it and/or get past it?

2. The giant golem is being controlled by little dudes inside of it.  How do we kill the little dudes inside this big dude?  Can we make a smoke bomb?  Can someone fit inside?

3. One of the little dudes is running for help.  Should we chase him down?  Who will go?

Without any surprises, the party will use the same stale tactics.

#7. The monster should reward.

XP is a boring reward.  Literally the worst.

Getting past the monster is often a sufficient reward on its own, if there is more cool dungeon to explore.

But also think about the other possible rewards that the players could get out of this encounter, and perhaps include some.

• A new ally.

• Information.

• Delicious monster parts to eat.

• Useful weapons and tools.

• Valuable gold or monster eggs.

• Weird consumables like potions and acid sacs.

• A new shortcut in the dungeon.