How to Use The Monster Making Tool

Something I’m often requested is a ‘How To’ on using my Monster Making tool. So, I suppose, I should do something about it.

First things first. The two most common emails I get are “How to make the monster’s name a noun” and “passive Perception is wrong!” If you want a noun for a name, preface the name with an asterisk (*). Passive Perception is calculated as follows:

10 + Wisdom Modifier if you do not add ‘passive Perception’ from the senses drop down. If you do add it, and the creature is not also proficient in Perception, the number will remain the same. If it is proficient in Perception, it will use 10 plus the Perception modifier. These are as per the rules on pg 279 of the DMG.

Let’s go over the steps of making a Monster. To help with this, please open your DM guide to page 275 (Creating a Monster Stat Block). Before we begin remember that anything which is a drop down or text field that allows you to type CAN be typed in with any custom text. If you want to make a size called “Silly”, just write it into the Size drop down and it’ll take.


First and most importantly: Choose a name. If your creature has a proper name and is not just a representative of its race, put an asterisk (*) infront of the name. That tells the tool to use it as a noun.

Remember that names have power, and knowing the true name of something gives you power over that thing. Also recall the general rules of fantasy names: If it looks like a lizard, it has a hundred s’s in it’s name. If it’s a demon, it either ate all the consonant or vowels before being named. When in doubt, find something familiar and switch the positions of letters.


Secondly pick a size. The program used to auto-change the hit dice of the creature, but it confused some people so that has been removed. Pretty simple stuff otherwise.


Third, choose a type. You do not need to choose a tag, as that’s only a modifier for some things in the game. However, if you do use a tag you’ll find it’s properly formatted in the stat block. And as with all fields, both of these can be customized with anything. Wanna put “Butt” as the creature type and “Fart” as the tag? Write them in and giggle away.


Fourth step is to choose alignment. Please note that monsters can choose (and by default have chosen) the Unaligned alignment, as they get all the fun. Again, this is fully editable to be whatever you want, should you need to add things like “Honourable” if you’re using the rules for honour.


The next step is to choose ability scores. Unlike the rules, I don’t have the restriction of 30 on a stat but gods help your players if you’re that sort of dm. The rules of the game say to look at existing monsters as a baseline to help you decide what to use, and I totally agree with that myself. If I’m not using an existing monster as a baseline I tend to use all 20’s because I’m cool like that.


Now, onto your expected Challenge Rating. If you hover over the drop down, you’ll find that it will tell you the various notable things about that CR. Something I want to note here, if you know what your CR is going to be ahead of time it’s probably best to select that part first.


Armour Class (yes, I’m Canadian and some words use ‘U’ in unfamiliar places) comes next. Either use another monster as a reference, the table on page 274 or (my personal preference) use the difficulty table from 238 because those numbers are pretty universal (at least to start). The AC and attack bonuses of things climb so much slower in this edition of D&D that those are really great baseline numbers to base most things on. The CR has suggestions for AC, which you could also use.


Step 8 is to determine hit points and size of hit die. So in my program you have two options: generate hp and roll hp. Roll will do exactly that: randomly determine hp. It’s nice, but by the book stick to Generate. It uses the average hp per die from this chapter.


Step 9 is to add resistances, immunities and vulnerabilities. Don’t forget the HP multiplier here to determine final CR does not actually get added to the creature HP. I made that mistake and my players were less than forgiving. To actually add these things look below “Damage Modification” in my application. The source is where it’s coming from, type is if it’s a resistance (half damage), immunity (total negation) of vulnerability (double damage). The exception text can be used for things like “except magical weapons” and probably will not be used much.


Step 10 and 11 actually go into a bit more depth in terms of the application, so watch carefully. First, click “Add Action” and you’ll see a new window pop up. This has three tabs, “Weapon Attack”, “Action” and “Reaction”. While self explanatory, I’ll still go into each one:

Weapon Attack: here you have the name (“Short Sword”), the type (“Melee weapon attack”), the bonus (3) and the target (“One creature”). The ‘On Hit’ area has three number areas: number of dice, size of dice and bonus damage (1, d6, 3) and a drop down for damage type (“Slashing”).

The next text area under that bit is to add whatever effects you’d like to do (“Creatures hit by the sword attack must make a strength saving throw DC 13 or be pushed 5 feet.”). If you use “and” as the first word in this box, you can chain your damage types. For example “and deal 3 (1d6) poison damage.” will be formatted just like attacks that deal multiple damage types in the monster manual.

Reach is for reach weapons, range is the close/far ranges you’d see on ranged weapons.

Action is for things that aren’t a weapon, but still need a description. The name and description fields are very straightforward. You’ll see some text in the description area as it will pull all the data from “Weapon Attack” (in case you wanted to manually edit that text). An example of a typical non-weapon action is the “Antennae” from the Rust Monster (MM p262).

Reaction works almost identical to action, except it doesn’t pull data from the weapon attacks. A creature that has a reaction can use these abilities in certain conditions, although only once per turn. Look at the Hobgoblin Warlord (MM p187) for an example.


Step 12 in the DMG is to determine Save DC’s. There’s no special trick to this as my app does all the work. It’s the creatures stat modifier, 8 and the proficiency from CR. There is an update scheduled to allow manual editing of this save modifier.


Step 13 is special traits, actions and reactions. Because actions and reactions were already dealt with in weapon attacks, I’ll talk more on abilities. When you click the “Add Ability” button, you’ll find a new window with two tabs: “Ability” and “Spellcasting”. Ability is for things like a Ghost’s “Ethereal Sight” ability. Passive traits that creatures have. Just add a name and description and you’re off!

Spellcasting is a much more complicated area, so let’s break that down. First, decide if the creature casts innate spells (like a Dryad) or learned spells (like an Archmage). If it’s the former, click the “Innate Spellcasting” button. This really just changes the boiler plate text about material components and what not. It also turns “Spell Level” into “Times per Day”

Next, select the type of spells the creature casts and the primary ability that the creature uses to cast spells. If the creature is not an Innate Caster, now is a good time to select how many spell slots they get for each level (look at an Archmage if you’re unsure of what a powerful caster looks like. Then look at a Lich because MWAHAHAHA those things are awesome).

Now the spell name and spell level are pretty obvious but if you wanted an example you could use level “3” and “Fireball”. Or level “2” and “Moonbeam”. If the creature casts innate spells, you’ll use this to determine how many times per day that spell can be cast, and the program will group them together later.

Once you add a spell, it’ll go into the box below. You can double click a spell to remove it.


Step 14 is Speed. The first one (“Speed”) is always listed, even if it’s 0. All other speeds only list if they are above 0. Fly will list “Hover” if you’ve clicked that checkbox. There is no real way to add additional types of movement, but if that were ever requested it could be added.


Step 15 is saving throw bonuses. Like players, monsters get these things to reflect what they’re good at. A tough creature gets bonuses to their Con saving throw or smart creatures get an Int saving throw bonus. These never include proficiency and will never show if they’re set to zero.


Step 16 is boring, but essential if you’re releasing your monster onto the web. Make sure to re-calculate their CR. I’m sorry about this, I really did try, but parsing all this information and making the program guess at a CR was simply too difficult because of how arbitrary information could be entered.


Step 18 is to add immunities which you probably did earlier with the vulnerabilities bit. Good on you for getting ahead.


Step 19 is to do senses. Now here is a big spot on my application that most people miss: passive Perception is had by ALL monsters. That’s 10 plus the creature wisdom modifier. If you want to add more than that, use the senses drop down to add ‘passive Perception’ and if the creature is also proficient in Perception, it will use 10 + the bonus of Perception. All other senses use the ‘distance’ box.


Languages is next, and I’ve pre-populated the list with everything except Telepathy. This box is editable, so put whatever you’d like (because you KNOW the Terrasque needs to speak French).


Lastly, something not in the DMG is Legendary actions. Because a Legendary Creature often has a Lair, this is a *very* difficult thing to create. My application has no ‘Lair’ information, so if you’re looking for it, I hope you read this paragraph and stop trying to find it.

The Legendary window that pops up has the “Name” which is only used for the big list of things the monster has in the main window (this doesn’t get put anywhere in the actual stat block). Then the ability name (“Tail Sweep”) and description. Adding it throws it into the box below confirming you entered everything right. Edit lets you fix the mistakes you made (happy accidents, sorry Bob).


And that’s it!