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D&D 5e House Rules: Combat Overhaul using the OODA Loop

929px-ooda-boyd-svg
Featured image of OODA Loop By Patrick Edwin Moran – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=3904554

<Edit> I just found a really unique to me house rule called Variant Shared Turn Combat on Reddit on the Unearthed Arcana subreddit and I’m amazed at the production value and quality ideas.</Edit>

The above diagram is a depiction of the OODA Loop which is a tool for understanding how people make decisions. Many of the ideas I will be presenting use this framework and come from my homebrew game I’ve been designing and redesigning for years that works very well when transferred to D&D 5e.

With the OODA Loop you have four steps: Observe, Orient, Decide and Act.

The general structure of combat in the PHB 5e on page 189 is as follows:

  1. Determine Surprise
  2. Establish Positions
  3. Roll Initiative
  4. Take turns
  5. Begin the next round.

There are many ways the DM can handle showing combat whether with miniatures, physical or virtual maps or overlays, or purely via imagination and description.

I prefer if possible to use the fog of war during the initial setup and not let players know things they can’t perceive if possible. Having a second map or description available just to the DM can make it easier to show the movement of NPC’s in the fog of war for the DM that the PC’s do not know about. It can be fun to flank the PC’s and get the PC’s to think about flanking especially with mounts or vehicles in play.

I also would like to say that D&D is not supposed to be simulationist and works just fine as is. I offer my system to people who like a little more complexity and options in their battles and to add a bit of tactical confusion and surprise. There are some changes that can make things very different in your game as it shifts priority away from Dexterity towards Wisdom but I think that is actually more balanced.

I have not playtested this at all with D&D so if you’re interested in trying it out and letting me know what you think that would be awesome. Please just leave a comment about your experience. If I forgot something obvious please let me know as well. It is easy to make mistakes on this kind of thing.

 

My System:

  1. Determine Surprise (Keep in mind the fog of war for step 2)
  2. Observe (Explain what each PC perceives and Establish Positions)
  3. Orient (Roll Initiative)
  4. Decide (Based on Initiative and what the PC/NPC perceives then declare actions)
  5. Act (Take Turns.)
  6. Next Round

1. Determine Surprise:

Nothing changed in this step.

2. Observe:

It is important at this point to go over what each PC perceives prior to Initiative so that they can form an idea of what is going on based on their personal perspective not that of a Player who can see much more. So, if an ooze is slinking behind the wizard and the wizard doesn’t know they obviously won’t be casting a spell at it. This encourages a bit of roleplaying so the very perceptive Rogue who sees the ooze approaching his ally can take a free action to yell “Behind you Mage!” after stabbing the Orc in front of her which might confuse the Orc while alerting the wizard so they may change their mind and cast burning hands in front of them rather in front.

The DM also needs to keep in mind what the NPC’s perceive and how they react. Experienced soldiers used to working in tandem with each other are going to be much more difficult to deal with than expert duelists used to working one on one or a mob of amateurs.

3. Orient:

Here things start to depart from the PHB 5e rules.

A big change here is that in my system Initiative is how well you observe your environment and process information rather than in the PHB which focuses on how fast you can move your body. After all, why would Dexterity have anything to do with how fast and well you can observe a combat, make a decision, and say “Shazaam!”? It makes a lot more sense to use Wisdom here to represent a combination of perception, common sense decision making, intuition, and actions and reactions especially those actions that don’t have any real physical component.

D20 + (Wisdom Modifier) + Proficiency Modifier/Die

For diceless Initiative just use the PC/NPC’s Proficiency Modifier and have an automatic 20 for the roll. For more variable Initiative use the optional rule for Proficiency Dice in the DMG on Page 263 which replaces, for example, the +2 Proficiency Modifier with a +1D4.

One could even use both in a game depending on the situation. Use the variable Initiative when surprise, “boss” battles, or unusual combat is happening and for the more normal lineup of good guys here and bad guys here just use the diceless version instead.

The reasoning behind using Wisdom here instead of Dexterity I provided above and my reasoning for using the proficiency bonus is that handling and reacting to combat is a matter of experience.

For example, take a reasonably healthy and elderly Special Forces combat veteran and mentally they will be able to process a combat situation faster and in a more capable fashion than a novice character with world-class Dexterity. Leveraging that experience to process the OODA Loop is a big part of improving decision making and thus performance in combat be it social, mental, or physical and you can substitute talent only so far when competing against old age and treachery.

Once you have everyone’s Initiative totals you can either post them for all to see or you can keep them to yourself.

The highest Initiative total provides the number of Combat Phases in this Combat Turn.

For example:

Rogue: 30, Ooze: 23, Wizard 22, Orc 22.

Thus, there are 30 Phases in this turn.

If two characters are acting the turn or movement during the same phase both actions take place at the same time. Thus, you can have both characters stab each other in the heart and this happened quite commonly in history or characters charging each other would meet at some point in between the two warriors rather than one warrior charging across the battlefield while the other sits there.

Any action that would take place at 0 Phase or when the combat phase is in the negatives all happen at the same time. Thus, a character who used their entire move before swinging a sword would have their action take place on the 0 phase along with any other characters.

4. Decide:

At this point starting with this highest phase the DM has the characters decide what they are going to do in a descending fashion phase by phase allowing the characters to have started their round and have their action/s take place during or after their phase depending on the type of action.

Each action, maneuver, spell, or movement takes place during or after the round/phase the character scored in the Orient step of Combat.

Remember you still have only the actions you can do just like in the PHB even if you still have leftover Initiative after you attack or cast a spell. If you don’t use it up with actions or movement you lose it. So, if you attack during phase 15 and don’t want to move you don’t get more attacks to do later unless you have the extra attacks feature.

I am going to introduce a term called tempo which has various definitions depending on the martial tradition or master but in this case, tempo means how long it takes to complete an action. Each action has a tempo cost which tells you how much later the action actually takes place in since your Initiative score is simply how fast you were able to process the combat situation not the time it takes to perform an action.

Some martial masters have used the idea of hand, body, foot, and feet to describe combat, reaction, and initiative. This means that the tempo of moving your hand is fast, moving your body is a bit slower, moving one foot is slower than that, and moving both feet is the slowest. In other words, swinging a sword at an opponent in measure is faster than moving your torso/body back to dodge or forward on an attack. Moving a foot forward or back takes even longer and moving both feet is the slowest. In other words, it is faster to thrust a blade with just an arm movement vs an arm movement plus moving the body forward with the arm vs the arm, the body, and a foot forward such as when lunging vs the arm, body, and both feet in a shuffling strike.

To put this in perspective it takes longer for a warrior to walk 30 feet and swing a two-handed warsword than it does for the rogue to move 5 feet and backstab with a sgian dubh knife even if the warrior rolled a higher Initiative score which is how things stand now.

A character can under this system postpone their action or be indecisive. For example, a pikeman could see cavaliers and their horses charging towards him and plant her pike and ready themselves for the charge postponing their attack until the cavalier comes in range. Should the cavalier stop rather than coming into range the pikeman could charge forward instead or drop the pike and draw the loaded crossbow at their side and fire thus allowing more flexibility than the current system at the cost of more complexity for the DM and players to handle.

Actions and their Tempo:

Attacks:

For a second attack, the action takes place after the first one and any movement has subtracted from the initial Initiative. Starting Initiative of 10 and a heavy strike for on phase 7 and a second heavy strike for -3 for an attack on phase 4.

If the character is not Familiar, Proficient, or Expert with the weapon then add +2 to the Initiative Cost.

Heavy and Light Weapons have that trait listed with all others without that trait being regarded as Medium below.

Heavy Weapon Attack (Melee or Ranged): 3 Initiative Cost.

Medium Weapon Attack (Melee or Ranged): 2 Initiative Cost.

Light Weapon Attack (Melee or Ranged: 1 Initiative Cost. (Most Unarmed Strikes)

Loading a Weapon: 5 Initiative Cost.

Magic:

Cantrip: 1 Initiative Cost.

Spells: (1 + Spell level) Initiative Cost.

Innate Spellcasting, Legendary Actions, and Special Abilities: 1 to 5. (DM should quickly decide based on the complexity and potency of the ability or power or the complexity of the situation.)

While the spellcaster is making magic they are vulnerable just as if they are Concentrating on a spell…because they are concentrating on the spell they are casting. This means not only does it take awhile to drop a major spell and thus adds difficulty to the tactical landscape it also means it is even more important to protect the big guns because if they take damage and lose concentration it can be the difference between an easy encounter and a deadly one.

For example, the Cleric has an Initiative of 15 and is casting a 6th level spell so their spell begins on Phase 15 and ends on Phase 8. If they get hit with a barrage of arrows and Magic Missiles they could lose Concentration and have their spell fizzle out. The spellcaster doesn’t lose the spell slot if they lose Concentration because they weren’t able to marshall the magic before getting distracted.

This can give a quick character a chance to use Arcana to recognize the spell the big baddie is casting and yell for the Archer to shoot the Wizard before they drop a Meteor Swarm on them. It also makes Counterspelling a bit more fun which counts as a Reaction below so it only has a 0 IC.

Skills, grappling, and non-combat actions like help, search, ): DM may add or subtract depending on the complexity of the skill use. This represents the simple automatic speed that develops from increased competency at a task. Picking a lock when you’re an expert and under pressure in combat is much faster than if you’re not an expert.

Unfamiliar: 4 Initiative Cost

Familiar: 3 Initiative Cost. (Jack of All Trades, Remarkable Athlete, or my house rule linked above.)

Proficient: 2 Initiative Cost.

Expert: 1 Initiative Cost.

Movement:

Walking (base movement): 3 Initiative Cost per 5 feet

Dash: 2 Initiative Cost per 5 feet.

Sprint: 1 Initiative Cost per 5 feet. (Dash without gear, weapons, or any substantial encumbrance such as dropping everything and running for your life from the greek fire armory that a mage dropped a delayed blast fireball inside.)

Breaking up your move:

Walk 15 feet for a 15 Initiative Cost then cast a spell and use the remaining X (15) feet to get back undercover on the 0 Phase.

Use Object: 1 to 5 Initiative Cost based on the complexity of the object. Opening a stuck door may take longer than pressing a button.

Mounting: 10 – Dexterity Modifier

Dropping Prone: 1 Initiative Cost.

Standing up from “Prone”: 10 – Dexterity Modifier

Disengage: 1 Initiative Cost.

Dodge: 0 Initiative Cost.

Free actions: 1 Initiative Cost.

Quick Look Around: 1 Initiative Cost. Let’s the character get a quick scan of the environment for obvious things that don’t require a roll. Since things change dynamically during the round this can be important.

Reactions like Opportunity Attacks: Usually have a 0 Initiative Cost and take place at effectively the same time as the action that caused the reaction such as a Shield spell blocking an arrow.

Bonus Actions: Can take place before, after, or at the same time. For example, a Shield Master could do a shove before they do their attack or after. A Two-Weapon fighter could thrust forward with both daggers in simultaneously on the same phase or one after the other.

5. Act

Using the earlier example: Rogue: 30, Ooze: 23, Wizard 22, Orc 22. Thus, there are 30 Combat Phases.

Starting with the highest Initiative Score have the highest scorer decide what they want to do. So, the Rogue at Phase 30 would say I am probably moving 5 feet forward to stab the Orc after a quick look around. On Phase 29 the DM would tell the Rogue that an Ooze is slouching towards the Wizard but about 30 feet away. The Rogue has to decide whether to tell the Wizard and alert the orc or move forward and backstab the orc. She decides he should be fine and walks toward the orc and sneak attacks. So, the DM would go through Phase 28, 27, 26 (sneak attack with sgian dubh a light weapon -1 IC) and on Phase 25 rolls for damage and kills the orc. Now on phase 24, she yells at the wizard “Behind you!”.

On phase 23 the Ooze starts sliming up to the Wizard but is 30 feet away. It will have closed five feet by phase 20. The Wizard on phase 22 panics and flings a firebolt cantrip at the Ooze without thinking and hits without killing the ooze. The cantrip had a cost of 1 IC so on phase 21 the Wizard turns and walks toward the Rogue keeping an eye on the ooze. Both the Wizard and Rogue move back to keep their distance from the creepy looking Ooze which decides to Dash on its remaining move to close the distance.

The DM would map out the movement as the phases would drop one by one. Any remaining movement would be used during Phase 0 for all three creatures.

Next Round:

The next round would start with either a new roll if the DM thinks the situation is very different like new creatures enter the combat arena or dynamically in a different “scene” or if the situation is relatively static just reuse the same totals from the previous rounds.

Hope this gives you some ideas on how to spice up your combat! Keep in mind that this system does penalize movement and powerful spellcasting the most. It does encourage more active protection of your spellcasters when they are casting spells and makes it a bit harder to unleash the big guns when not protected by the tanks/front line.

 

D&D House Rules:

Combat Overhaul

Shields

Character Creation Backgrounds

Crafting, Magic Items, and Economics

Familiarity vs Proficiency

Character Focus

Tactics of Mistake

Counterattacking

 

 

 

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8 responses to “D&D 5e House Rules: Combat Overhaul using the OODA Loop

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