So you’ve decided that it’s time to create a unique creature for your characters to face in a DnD campaign? Well, I was hoping you’d say that! Welcome to the exciting world of homebrewing your own monsters.
As a DM, creating your own creatures can be a very rewarding experience and add a whole new level of excitement to your players’ adventures. Whether you want to create a friendly monster to aid your players in their quest, or the most terrifying beast who will pose a massive challenge in combat, it’s up to you, but both will inject a lot of creativity and let your personality shine through in the game.
In this quick and easy DnD homebrew monster guide, I’ll take you through the necessary steps of creating your own creature, giving you the tools to make even your wildest dreams a reality. So, let’s get started!
Come Up With a Concept
The first part of the build-a-monster process is all about figuring out the basics aka what you want them to look like. When choosing your monster type, you should take your setting into account. If your characters are frolicking around the forest, a sand monster might seem a bit out of place, but a plant-themed one would be a perfect fit. Or if they’re exploring underwater – don’t exactly use one with fire powers because it would be utterly useless.
If you don’t know where to start, you can try getting inspiration from your favorite book, movie, TV show, or even some monster artwork you find online. This is all well and good, but the best method for beginners is to use the creatures from the Monster Manual as a jumping-off point and tweak them a little bit to fit your creative vision.
At this point, you should also start thinking about the monster’s place in your story. Why is it there? Why does it seem to have beef with the party? How does the monster fit into your overall story – is the creature just cannon fodder for the group or is it part of a larger narrative? If the creature is going to be a large part of the story, you should also give them a backstory and some personality.
Create a Stat Block For Your Monster
To make our new monster’s stat block, we’re going to borrow from the Monster Manual again. You know what they say – imitation is the sincerest form of flattery – so this just goes to show how amazing of a book Monster Manual is. Also, we’re kinda lazy too, and looking for a shortcut, but let’s skip over that part for now.
But how will you know which monster’s stat block to choose? Great question! We’ll try to find something similar in appearance, size, or abilities to the creature we’re trying to create. Let me give you a few examples.
Example 1: If we’re intending on making a stocky creature with water-bending power, we can take inspiration from an Azer, a medium fire elemental.
Example 2: If you’re in a forest setting and want to make something like an evil Groot, then you can tweak a Twig Blight to fit your narrative – increase its size, add fire and projectile resistance, and the ability to cast nature-themed magic.
Example 3: In case your players are currently playing a horror module and find themselves in a graveyard at night, how about you add a Dementor-like creature? You can take inspiration from a Devourer, a nasty little fiend who likes to consume the bodies and souls of humanoids.
Example 4: If your party loves Dune, and is roaming the desert at the moment, then why not create an encounter with a Shai Hulud aka Sandworm? The closest thing to this behemoth of a monster is a Purple Worm, so you can use his stats with a few little changes. I would increase the HP in order to properly convey how huge this creature is, bump up its speed too and of course, alter the appearance too.
The Monster Manual is pretty detailed and contains tons and tons of different creatures you can build on, so chances are, anything you can think about can be adapted from it (if you’re creative enough).
If you’re really ambitious and want to go above and beyond for your group, you can do it all from scratch. But beware, this is a long and strenuous process and can be quite challenging too. Nevertheless, if I still didn’t scare you away, you can find detailed instructions on page 273 of the Dungeon Master’s Guide.
Give Your Monster Some Cool Abilities
This is the time when you choose which attacks, defenses, and special abilities your new creatures have. A very cool way to modify already existing monsters is to steal ideas from other similar ones.
Example 1: To our water-bending Azer I would give the special abilities of a Water Elemental – Water Form which would let them move through narrow spaces and Freeze which means they will partially solidify when taking cold damage. Also, make the creature Amphibious like Merfolk or a Sea Hag. They can also be slippery and have an advantage on ability checks and saving throws made to escape a grapple, like the fishlike humanoid Kua Toa. Add a harpoon for melee and ranged attacks and you’ve got yourself a completely new monster ready to go!
Example 2: In order for the Twig Blight to truly embody Groot, I would add all the features of a Plantaemancer e.g. the ability to communicate with plants and manipulate them, or summon the power of nature to exact your rage on enemies. Also, I would make use of the Vine Blight traits Constrict and Entangling Plants too, to make the ultimate plant monster.
Example 3: The first thing I’d add to a Devourer is the ability to fly, then maybe a Banshee’s Horrifying Visage
Example 4: To make a convincing Sandworm, I would add a few attacks like Constrict, Swallow, and Smash. Keep the Purple Worm’s Tunneler ability, though, that makes a lot of sense! Also, since Sandworms’ Achilles heel is water, let’s add a disadvantage for attacks that contain it. If you want to make a different size range of Sandworms, you should fiddle with the HP and XP points they bring.
Figure Out the Monster’s Challenge Rating
The last part of our DnD homebrew monster guide aka calculating your creations’ challenge rating (CR) is definitely the trickiest of them all, but not impossible by any means.
Fake It Till You Make It
The first step may sound a bit counterintuitive, but bear with me – you need to estimate your monster’s challenge rating. You don’t have to be super precise at this point since we’ll get the exact value at a later point. How would you go about doing that? Well, you should create one that’s a great fit for your party, and for a monster to pose a decent challenge for your party, its challenge rating should be equal to the characters’ level. So for our hypothetical four-player party with level 5 characters, I would choose a monster with a CR 5. Now that we’ve got our initial value, let’s move on to the next step.
How to Calculate the Challenge Rating
We’ve arrived at the math part of figuring out the CR. Don’t give up now, it’s the final stretch! The “total” challenge rating depends on the Offensive CR and the Defensive CR, so let’s calculate those first.
A Good Defense Is the Best Offense
The Defensive CR value of your monster will depend on its HP. So at this point, you’ll use a table named Monster Statistics by Challenge Rating which you can find on page 274 of the Dungeon Master’s Guide. Just to give you an example, I’ll pretend I created the Bone Devil on page 71 of the Monster Manual. This creature has 142 HP and 19 AC.
The first step is to see which CR range the Bone Devil’s HP fits. Since it’s 142, it’s a perfect fit for CR 5 (131-145).
The next step is to compare the AC scores. The Bone Devil’s is 19, and monsters of CR 5 usually have only 15. This is where we need to make slight alterations. The general rule of thumb is to bump up the CR by one point if your AC is two higher or lower than the one in the table. So since we have a difference of four AC points, we’ll bump up the Bone Devil’s Defensive CR from 5 to 7.
We’ll follow a very similar process for the Offensive CR value, but first, we’ll have to calculate Bone Devil’s damage per round. Since this creature makes three attacks in total, two with its claws (1d8+4 slashing damage) and one with its sting (2d8+4 piercing damage + another 5d6 poison damage), the max damage it can deal per round is 74.
If we consult our handy dandy Monster Statistics by Challenge Rating table again, we’ll see that this damage-per-round score gives our Bone Devil a CR score of 11. Now we compare the expected attack bonus for a CR 11 monster (+8) and compare it to the Bone Devil’s (+4). Now we’ll apply the same logic as with AC in the Defensive CR. Since our monster’s attack bonus is four points lower than the expected one, we’ll bump the Offensive CR value up by two, making it 13.
Average It Up!
Finally, we sum the two up and take the average – which is 10 – so that’s our Bone Devil’s final Challenge Rating.
Take a Shortcut
If this seems too labor-intensive and complicated, I’ve got an easier route for you – there are many Challenge Rating Calculators available online that will make this tedious job feel like a breeze, so find one that you like and be sure to bookmark it for future uses!
