Effectively running combat for one-on-one 5E is a major area of concern for many GMs. After all, the monster challenge ratings, player options, and adventure and encounter design guidelines all assume parties of at least four adventurers. When you play one-on-one, those assumptions don’t necessarily work. So how can GMs build encounters that are challenging for the party without being more deadly than planned? How do we adapt and balance creatures and combat to keep the stakes fun and interesting? Below, we cover three tips for scaling combat for one-on-one 5E: understanding action economy, tweaking stat blocks, and incorporating allies.
The Almighty Action Economy
Action economy refers to how many actions opposing forces are able to take in a round. The more actions that one side has, the more things they can do and the more powerful that group is. Thinking about action economy in this way helps us remember to not just consider the number of combatants in an encounter: we also need to factor in the number of actions those combatants have available.
We learned this lesson the hard way early on in our game with an encounter that, in terms of challenge rating, should have been difficult but fine for our party of two. However, the PC and GMPC quickly became overwhelmed by facing eight combatants, even though the combatants’ CR was very low. In their action economy, the party was outnumbered 4:1—that’s a lot of potential damage to take each round!
In 5E, even a powerful adventurer is going to have a hard time if they find themselves alone and greatly outnumbered. These considerations compound when we consider the type of creature the character is fighting and any special abilities it might have. For instance, features like multiattack or pack tactics, spells like hold person or slow, and maneuvers like grapple and restrain are all going to have an impact on the action economy and can quickly tilt combat for (or against) your party.
Reducing the number of enemies your party is fighting can help combat flow more quickly while also making it weightier. For example, as the GM, you can emphasize the mighty crunching terror of one careening ogre as opposed to a group of goblins. A fight with Gorgulax the Hope Gnasher is more exciting than fending off unnamed goblins any day.
So the next time you’re building an encounter for your 1-1 5E game, don’t stop with the number of foes your party will face—double-check how many actions those foes have in comparison with your party.
This may not work out perfectly each time, but don’t worry! You can always add in enemies or allies as needed if a combat is turning differently than planned, especially if the party is in trouble and isn’t in a good spot to run away. The enemy combatants might have other foes in the region, or a secret ally who’s been following the party could leap down from the trees, ready to turn the tide in their favor.
Tweak the Stats
In addition to the special abilities listed earlier, higher-level creatures have access to legendary actions that shift the action economy in their favor. In effect, this makes one combatant (such as an adult green dragon) that much more formidable. If you mix in the lair actions as well, you have one creature that might have five or more actions in a round. Should we just throw those out when playing one-on-one, or are there more creative solutions?
What if, in this scenario, the party had a chance to prepare before their combat with the green dragon, and they receive a blessing from a powerful ally or guide? You could then grant the PC a few extra actions for this combat (we’ll call them heroic actions), which would significantly increase their versatility in an encounter. Ideally, these heroic actions would be themed around your PC’s other abilities or simply allow them to use those abilities more frequently. This would make for a special and memorable combat where your player would feel all the more powerful and awesome as they take on challenges that they would otherwise have never dreamed of besting. Combat is all about choices: by granting your player additional actions, you are increasing the number of choices they get to make!
We can find other solutions if we dive into the creature’s abilities—what else makes them powerful? A potion of heroism could help with saving throws against being frightened, and a potion of resistance (poison) would help against the dragon’s poison breath, which does a significant amount of damage (16d6!) whether a creature makes its Constitution save or not.
You might also consider taking away abilities like legendary resistances that would negate the limited resources of one PC and their party.
Don’t Fight Alone
You can run a great game with just one PC and one GM without the player needing to run a handful of characters all on their own. Juggling several characters can be cumbersome for the player, and it might get in the way of them developing a thoughtful, fleshed-out character, which is part of what many people deeply love about playing one-on-one!
We hope that the guidelines above have helped empower you to tweak statblocks as needed for your individual gaming table, but we have one additional way to tip the action scales in the PC’s favor—give them someone to fight alongside!
Adventuring with a GMPC and/or a companion character opens up possibilities in combat encounters that are harder to manage with just one character. Characters can work together and develop more robust schemes to solve the various problems they face on their adventures, be it sneaking into a vault or removing enemy combatants from the initiative order.
For companion characters, look at giving the player either a statblock or a simplified character sheet. They’ll still have everything they need to run the character, but they can save their most intriguing ideas for their PC and stay immersed in the combat without getting overwhelmed. We covered special considerations for GMPCs earlier in this series, which you can find here! The ideas covered in that post also apply to add-on characters that you give to your player.
Your primary consideration when running combat for your 1-1 game is to have fun! If things are turning into a slog or you and your player are not having a good time, switch it up, make a change, or take a break.
Combats can be taxing, so pay attention to your collective energy levels. Once the dramatic question has been answered (can the players survive, catch the bad guy, protect the prince, and so on), then is it necessary to play out each subsequent round, or can you step back from the initiative order and let the player summarize what they’d like to do to close out the fight?
Since a one-on-one game only has a pair of people involved, the two of you get to make all the decisions—make the ones that are the most fun!
You can find more advice and ideas for one-on-one play at dndduet.com.