D&D Homebrewery Guide - Creatures

Creatures and Non-Player Characters are easy to make once you understand what they're made of. The down side is that having a solid grasp of what makes a creature requires a lot of reading, followed by a fair amount of experimentation and play testing.

When designing a creature, the very first thing you should do is start with a concept. Everything in the game is supposed to represent something as though it were a real thing. The game rules and creature traits are simply a means to that end.

Once you know what you want to represent, the next thing you should do is hit the Monster Manual. Browse through and look for similar creatures. Don't just look for creatures which are conceptually similar either, look also for creatures with mechanical properties which sound like something your creature would do. You might find a creature which is almost exactly what you're trying to do mechanically.

Creature Name
When coming up with a creature's name, try to think of something snappy or that relates to the concept of the creature. The name should be capitalised wherever appropriate (which is context-based). At the very least, it has to be capitalised in the title of the page.

Size
This is the size of the creature (obviously!). A creature's size is important, as it decides hit dice (which will be discussed later on), and also describes how much area the creature occupies if used in tabletop tactical combat.

This should be capitalised. If your creature is a swarm, this is the size of the whole swarm, not the size of the individual creatures that compose it.

Swarm
If your creature is a swarm of lesser creatures, it should have the swarm feature, and the size of the creatures in the swarm should be listed here, not the size of the swarm itself. Most swarms are Medium and composed of Tiny creatures.

Type
This is the creature's type. A creature can have only one type.

Race
If your creature belongs to a race (e.g. Human, Elf, Devil), it should be listed here. Most Non-Player Characters can be of any race, represented by "any race", not "any".

Alignment
This is the creature's alignment. It should be listed in full (i.e. chaotic neutral or lawful good instead of CN or LG).

Armor Class (AC)
This is the AC of your creature. (Armour. If your creature wears armour or uses a shield, list so here. Natural armour should be called "natural armour" and not "natural".)

Hit Points (Hit Dice)
This is an integral part of creature creation. Hit dice determine how many hit points a creature has, and are determined by size.

A general rule for hit point calculation is Hit Dice + (# of Hit Dice multiplied by their Constitution Modifier) = the Creature's Hit Points.

Speed
This is the creature's speed. Most creatures have a main speed of around 30 feet, though some (like horses) move faster. If a creature has special movement modes, such as flight, include these here.

Speeds should be listed alphabetically, with its land-based movement (if any) listed first, for example, 30 ft., fly 30 ft., swim 20 ft.

Ability Scores
These are your creature's ability scores. Ability scores can be no lower than 1 and no higher than 30. All Ability Modifiers should also be listed accordingly.

Saving Throws
If a creature has a bonus to certain saving throws, list them here. If a creature doesn't have any bonuses, leave this space blank. The name of the ability score should be in capital letters, but only the first three letters of the score need to be used (i.e. Cha, not CHA or Charisma).

Skills
If a creature has a bonus to certain skills, list them here. If a creature doesn't have any bonuses, leave this space blank. The names of skills should be in capital letters and listed in full (i.e. Stealth not Stl or STEALTH).

Damage Vulnerabilities
These are the creature's damage vulnerabilities. A creature vulnerable to a certain type of damage takes double the damage when subjected to that type of damage. Creatures are rarely vulnerable to more than one type of damage. Certain vulnerabilities have more impact on a creature than others.

If a creature doesn't have any damage vulnerabilities, leave this space unchanged or blank.

Damage Resistances
These are a creature's damage resistances. A creature resistant to a certain type of damage takes half the damage when subjected to that type of damage. Commonly resisted damage types include cold and fire. If a creature doesn't have any damage resistances, leave this space unchanged or blank.

Damage Immunities
These are a creature's damage immunities. A creature immune to a certain type of damage takes no damage when subjected to that type of damage. For example, most undead and fiends are immune to poison damage. If a creature doesn't have any damage immunities, leave this space unchanged or blank.

Condition Immunities
These are a creature's condition immunities. A creature immune to a certain type of condition cannot be afflicted with that condition. Most undead and fiends are immune to the poisoned condition, for example, while a creature that permanently hovers (such as a ghost) would be immune to the prone condition.

If a creature doesn't have any condition immunities, leave this space unchanged or blank.

Senses
Passive Perception and any special modes of sight here. Many creatures have darkvision, which is identical to that of a Dwarf or Elf, but some have other senses, like blindsight or truesight. Special senses should be listed alphabetically (blindsight, then darkvision, then tremorsense, then truesight), and go before the passive Perception score).

If a creature has blindsight but can't see otherwise, it should be listed as such in parentheses. Senses have no impact on Challenge Rating, but some impede or render certain effects useless, such as blindsight and the blur spell).

Languages
List the languages the creature can speak or understand here. Languages spoken have no impact on a creature's Challenge Rating, but a creature that speaks many languages will have an advantage in social interaction, mainly because it might speak languages that it or its followers can understand, but that the Player Characters might not.

If a creature speaks no languages, represent it with a dash (—). A creature with telepathy should have its ability listed here with a range in feet. If its telepathy is limited in some way, it should be represented with the Limited Telepathy feature. Having a language restriction on telepathy isn't cause for it to have limited telepathy.

Description
This is the description of the creature. Important things to consider include what the creature looks like, sounds like, smells like, feels like, and tastes like (if applicable), some typical behaviours, some lore or culture (if applicable) and some battle tactics the the usual specimen might follow.

Does it keep other creatures as mounts or companions? Does it usually form groups, or is it solitary? What is its preferred diet (if it does eat)? What is its usual habitat (temperate forests, deserts etc.)? What does the creature make/wear? What is it known for doing?

Special traits and features that the monster shows are listed here. Common traits include Spellcasting, Innate Spellcasting, and Keen Senses.

Traits should have distinct effects. When creating a trait, consider if it would be better as part of the description. For example, if a trait mentions that that other creatures mindlessly obey your creature, you should list that in the description, not as a trait, but if it used magic to do so, consider granting it the Spellcasting or Innate Spellcasting feature and the ability to cast one or more enchantment spells.

Actions
Actions are effectively a list of all the actions that a creature can make. If unsure of how to format these actions, refer to a Creature Stat-Block found in an official publication.

Reactions
If the creature can use its reaction for something special (standard uses for reactions — like the opportunity attack — don't need to be listed here. It is assumed the creature can perform these), list them here. A common example is Parry.

Legendary Actions
The can take three Legendary Actions. Only one Legendary Action option can be used at a time and only at the end of another creature's turn. The regains spent Legendary Actions at the start of its turn.

General

 * Hit points should always be listed as such, and never be called "HP" or "health".
 * Feet (measure of distance) should always be listed as ft. (in movement, range of telepathy and special senses, and the reach or range of attacks), or foot or feet (where appropriate) everywhere else. Don't use an apostrophe at the end of the number!
 * All references to ability scores should have the score's name listed in full (except for saving throw bonuses, as detailed in the section above). Only the first letter should be capitalised (i.e. Intelligence, not INT).
 * Nothing has "an advantage" or "a disadvantage". It has "advantage" or "disadvantage". Similarly, nothing has "a vulnerability", "a resistance", or "an immunity". It has "vulnerability", "resistance", or "immunity".
 * DC should always be listed in capitals, not "dc". The DC of a saving throw should come before the relative ability score, and not in brackets (except when detailing the escape DC for a grapple). For example, DC X {ability} saving throw/check, not {ability} saving throw/check (DC X). Similarly, AC should also always be in capitals, never "ac".
 * A creature can be immune to conditions, but it can't resist them. Instead, give it a trait that grants it advantage on saving throws against that condition. Sometimes, it might be more appropriate to grant advantage on certain saving throws against that condition, such as the Sure-Footed trait of the goat.