Steps to Scenario Design

There are countless ways to design a scenario for a role-playing game like Dungeons & Dragons (D&D), and it can be intimidating to new DMs to try and figure out what will work best for them. In this article, I’ll explain a general approach to scenarios that you can use to start, knowing that it is highly encouraged to start creating your own style.

The short advice is that you will develop your own style over time, and many people will be quick to say that you should just trust yourself and go with what feels right. This can be intimidating to the new DM as the incredibly broad and open world of possibilities can feel like an endless sea of potential mistakes. So, the first step is to acknowledge that


  1. Accept that you will make mistakes
  2. Work with the games mechanics to guide your creativity
  3. Choose an objective for the scenario; what does the party want?
  4. Pick a setting and theme to work with the objective
  5. Create a suitable antagonist for the players; who opposes what they want?
  6. Fill in the finer details at the end: treasures, traps, environmental affects, places to tell story, etc
  7. Review and revise, but be ready to improvise!

1 – You will make mistakes

The largest take-away from this is to give yourself permission to try things, experiment, and just have fun. Mistakes are not always a bad thing either, and you might have underestimated how something you put little thought into turns out to be what is the most fun for your table. Being open to these mistakes is what will allow you to dive into these unexpected developments rather than trying your best to coerce the players into what you originally imagined.

2 – Mechanics

There are two crucial numbers to help start: experience budgets. In the Dungeon Master’s Guide, on page 82 and 84, there is a table to help you gauge the amount of experience players can handle in a day (before taking a long rest), and what monsters that the players can handle by difficulty (eg. easy, medium, hard, deadly). Both tables will list the experience by player level, which you multiply by the number of players. Don’t forget NPCs!

For example, let’s look at a group of 4 players at level 5. In the adventuring day xp, a level 5 character can handle 3500xp. Since there 4 players, that’s 4*3500 which equals 14,000.

Now that we have that, let’s see what the maximum challenge of a monster they can handle is. In the Xp threshold chart, a level 5 character will have a deadly encounter with a monster that gives 1100xp. A group of 4 players at level 5 will have a deadly encounter with 1 monster worth 1100xp, multiplied by the number of players is 4400xp. This amount is closest to a CR8 or CR9 creature. Which one to round to will be your judgment based on the players at your table.

Note: Challenge Ratings are meant to be a short-hand reference to the creatures “level” as they will challenge a party. A level 9 creature should be able to challenge a single level 9 player.

What if you want to use more than 1 monster?

On page 82 there is also a table to account for multiple creatures. I typically expect the party to deal with 1 major threat, or multiples, like 3 to 6. To help decide this, we can work backwards from the 4400xp total. If there are 3 to 6 creatures, you should multiply the xp of the creature by 2 in order to account for the enemies group size. So what creatures can we use to make up a group of 6 to challenge the party?

Take the 4400xp and divide by 6 (the multiplier for the number of creatures), and then by 2 (the multiplier for the enemy group size). In this case, the result is 733xp. The closest challenge rating to this is 700xp (CR3).

What we know now is that we can use a single monster worth 4400xp or a group of 6 enemies worth 700xp.

How many encounters should you use?

Now is when you take that adventuring day xp and divide it by the Xp threshold. In this case, you have 14,000xp divided by a deadly encounter worth 4400xp, which gives us roughly 3 encounters. Those three encounters can be a single creature or 3-6, but try to keep the encounters separate to give a chance for a short rest.

3 – Story Objective

Having the mechanics figured out, you should now consider what the objective of this scenario is. It is almost always the case that the players want something, but someone else wants it more or is in their way. This can be as simple as wanting to cross a bridge, and a knight wants to stop them. It can also be as complicated as a player wanting to win the love of a character, but that characters history of grief is preventing them from being able to.

“It is almost always the case that the players want something, but someone else wants it more or is in their way. “

Whatever the objective is depends on the story you and the players want to tell. If you’re just starting out, ask what the players are looking to achieve, and think of a character that would oppose that. The first session doesn’t even need to be a combat encounter, and can entirely be a role play session to figure out what the players want to do.

Six NPCs Your Campaign Should Have

In any case, your scenario will have an objective that the players are looking to accomplish. In this example, let’s say that our group of 4 players is trying to rescue a town from a goblin attack. The players all arrived at the town at the same time, but they are the only well equipped adventurers, so it is up to them to help save this small city from goblins. Their objective is to keep the citizens alive, while the goblins objective is the opposite: to kill them all and take their stuff. The most basic objective of all, but very effective to start!

4 – Setting & Theme

Where is this all taking place? And Why?

This is like the canvas for your story, and the monsters and characters are the colors that will give it life. But what is there already?

Examples include a city, small town, dungeon, cave, and more. Whatever you choose for your setting, ask if it fits the objective. Is it inspiring to you? Is there a story to be told here? Is there a theme of some sort that can connect it all together?

I find the particular details can be best filled in at the end, but for now it’s best to ask what the setting is and, if the inspiration strikes you, why the story is there.

5 – The Antagonist

I find this part to be the most fun, because it is simply figuring out who the opposition to the party is. You already know the Xp thresholds, so you can look at the D&D books like the monsters manual to see what creatures to try out. There are two ways of doing this:

  1. Look for monsters that fit the criteria of the Xp thresholds. You can look through the books and find a single monster of CR9, and a monster of CR3 that you can make up a large group of 3-6.
  2. Find the creature that you want to use and what it takes to make them a challenge.

In our example, you know that you can do three encounters in this scenario, so you could say one encounter is the boss (one CR9), and two encounters and the pre-amble to the boss (two groups of CR3).

Looking in the monsters manual, I found that the hell hound is a CR3, and it makes sense that a group of goblins could have some hounds. That is already 1 encounter! A group of 6 hell hounds will attack the party when they first arrive at the city.

Now to make the goblins work. A goblin is pretty weak and only worth 50xp, while the boss is worth 200xp. Let’s focus on a group of the weaker ones first.

We know that a deadly encounter is worth 4400xp, and a group of 6 goblins would be worth 700xp ((50*6)*2). This is not challenging enough for the party. So let’s beef up the enemy party with something big along with them. We will aim for a group of 6, where 5 of them are goblins. That means we so far have 500xp total ((50xp(Goblins)*2(Group multiplier))*5(party size) or (50xp*5)*2). The strong addition should make up the difference which is (4400-500)/2 or (4400(Xp threshold)-500(the total so far)/2(party size multiplier) which gives us 1950xp, or CR5.

Let’s take a look at CR5 and what could fit a party of 5 goblins. What gets my attention is the gladiator because, here’s the best part about D&D, you can use the stat block of the gladiator for a beefy Goblin! While you could just say that a gladiator is in the group of goblins, and create your own story around why, you could just as easily say that there’s an unusually strong tall and strong goblin with the party and use the stats of the gladiator for them.

Lastly, the boss encounter. A Goblin boss is only worth 200xp, which is not challenging enough for the 4400xp threshold. At this point, you’ll know the tricks from before to paint a picture of the boss encounter, whether the Goblin boss is accompanied by another strong creature, or if you want to use another stat block for a unique Goblin creature.

Don’t worry. You’ll probably make a mistake, and that’s part of the game.

6 – Filling In

At this point, you have your number of encounters, choice of antagonists, a setting, and an objective. Get ready for the most fun part of all: the details. This includes the treasures, traps, environmental hazards, exposition, and more.

A) Treasure

On page 136 of the dungeon master’s guide is table for treasures. You can roll the treasure per individual creature or by hoard. To start off, I would roll on the hoard table for the level of your party. In our example so far, it would be the CR5-10 table because our players are level 5.

Roll up the coins to be found at the top, then roll a d100 for the rest to see what treasures can arise in the scenario. Definitely feel free to re-roll or just choose whatever treasure you think would make sense. These tables are only a suggested starting point. Your job will be to decide how much treasure the party should get and if the strength of the item makes sense.

Be mindful of what treasures players have already got, who should get more, etc. But also ask what treasure makes sense to be found in the setting so far. From here, you’ll be able to fill in the details.

Don’t forget potions of healing!

B) Traps

On page 121 of the dungeon master’s guide is a table for traps. This can also be found on the official DM screen. It is broken up for character level, trap level, and the traps dc or attack bonus. What the trap is exactly is up to you!

In our example, I might imagine the goblins set up a net trap, intended to set the players back, but not kill them. So, let’s pick the DC of the net trap. It is just setback, so it’s DC is 10 or 11. I’ll say 11 for now, because I want to challenge a bit more than go easy. I’ll say that the net trap is hidden in the debris of a streets rubbish, and if the players do not have a passive perception above 11 then they do not see it. Once the trap goes off, they will have to roll a saving throw against the trap of suffer the effects, in this case being grappled. I think dexterity makes the most sense for a net trap, so they will have to make a dexterity saving throw against 11 or be trapped.

Whatever happens next depends on the story so far. Whether it be the goblins coming and attacking, or just the party trying to escape. You’ll have to trust yourself to judge it in the moment. Feel free to move the location of traps to make them more dramatic or included in the story. You don’t need to feel contrived by your own design. If the players never go into the alleyway of the trap, then the encounter will never happen! But if the players try to sneak up on the goblins, that’s the perfect place to move it!

C) Environmental Hazards

What is happening in the setting? Is there bad weather? Other people? Potential danger? Consider that the traps could just be the sandstorms of a desert, or the fire of a volcano. In our example, they are in a city, so it seems perfectly fitting that people in a panic is an obstacle. This can be as simple as a goblin taking a hostage, or a group of panicked people charging into the players: make a dexterity saving throw or be trampled by the people!

Whatever the hazards you choose, consider it the spice of the scenario; just a touch lets the party know there’s a world outside of them, but too much will spoil it and feel overwhelming. A group of panicked people running out of the town square adds flavour to the encounter, but a town riot is no longer about the goblins attacking, now is it?

D) Exposition

Finally, why is this all happening? And how does the party learn about it?

This is not always complicated at all. Goblins could attack a city just because they want money, and the human city has a lot of money.

It can get as complicated as political intrigue, and that the Goblins were hired by a group of nobles that do not like a group of people in the city. They paid the Goblins to attack the city, but namely loot only a specific section of the city.

In either case, how does the party find this out is up to the party! But you can prepare some likely choices that they make. More often than not, it’s directly from the antagonist; the Goblins themselves. It is more than likely that this party will interrogate a Goblin and ask why they are attacking. This is where you can choose between something as simple (yet effective) as “Because we wants money!” or as intriguing (but more in depth) as “Because you humans paid us to!”. The latter will cause the players to ask questions like who and why, and this is where you can start to create a chain of characters and events that lead to the overall story of this city!

Finally, polish it off!

Look back on what you have so far. Take a break and come back to it later. A fresh mind will have new ideas and new perspectives. On the other hand, stop working so hard and trust in the adventure of improvisation. It can be tremendously rewarding to have little to no preparation and yet continue to create an adventure with your friends.

The most important thing of all is to remember that mistakes will be made, and in doing so, you will see what works best, and what is most fun for you all. Over time, you’ll learn what challenges the party, what characters they like more than others, and what kind of story they want to tell.

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