Monster Building Guide

Contents

Creating a Monster from Scratch

There are 5 steps to create a monster:

  • Having a cool idea in mind
  • Tier and Challenge Points
  • Building a Sheet
  • Abilities and other Actions
  • Damage per Turn

Having a Cool Idea in Mind

Maybe you saw a cool picture of a monster, or watched a film featuring a specific monster, or perhaps you came up with a new idea that just popped into your mind.

Regardless, when creating a monster, you should have a clear concept or gimmick that you are aiming for.

A good monster should always have its unique feature or gimmick reflected in its stat block, creating a memorable encounter for your players.

As a monster creator, you are essentially a game designer, and a good designer always asks multiple questions when creating something.

For instance, does this monster pose a challenge to my players, or does it merely frustrate them? Remember, the primary goal of the game is to have fun.

Tier and Challenge Points

Now that you have a cool idea in mind, it’s time to think about the power level of your creature.

A good rule of thumb is to start by considering the Tier of your players and adjust the details as necessary. The Challenge Points you assign will reflect whether the creature is more of a boss or a minion.

The higher the Challenge Points, the stronger the creature will be on its own, and it will tend to function as more of a boss. Conversely, lower Challenge Points will result in a weaker creature that is better suited for the role of a minion.

Building a Sheet

The sheet of a monster should always try to reflect that monster’s gimmick. Don’t be afraid to create your own abilities and Attacks. However, it is very important to know the basic rules to create a monster sheet.

The monster sheet should always these 3 things:

  • Stats + Skills
  • Attributes
  • Abilities & other Actions

Stats + Skills

This is the heart of the system. You are going to use skills for all Checks, Saves, and Attacks.

Normally, players need to choose the skills in which they will invest their skill points. However, this rule does not apply to monsters! To simplify their character sheets, both their stats and skill bonuses are displayed together.

For example, if you encounter a Tier 3 monster with +7 Strength, it actually means that the monster has a base Strength of +4, and it has invested 3 skill points into all skills related to Strength.

Having a high Luck stat means that the Critical Hits from your monsters will be stronger, and that you can have Luck Points to use against your players.

Having a low Luck stat means that the Critical Hits from your monsters will be low, and you won’t have to worry about one-shotting your players. It can also increase the chances of a Critical Fail, which in turn can counterbalance a monster with multiple Attacks.

Attributes

Once you have decided on the Stats & Skills of your monster, you can then define its attributes, which are directly affected by its skills.

Here is a list of all the attributes that a monster can have:

  • Monster Type
  • Size
  • XP
  • Special Loot
  • AC & AP
  • Posture/ HP
  • Damage Immunities/ Resistances/ Weakness
  • Passive Perception/ Insight
  • Senses
  • Language
  • Movement

Monster Type

A lot can be determined from the Monster Type. You expect an Elemental to act differently from an undead for example.

The types of monsters are:

  • Aberration: Cosmic and alien entities.
  • Beast: Includes common animals, extinct animals, or even non-historical ones.
  • Celestial: Angels, Quetzalcóat and other creatures of a higher state of being
  • Colossus: A giant creature of great strength and size…
  • Construct: An animated object, an artificially created creature, such as golems and others.
  • Draconic: A dragon is a reptilian creature, usually winged, often having supernatural abilities. Draconic creatures include dragons and other dragon-like creatures.
  • Elemental: An Elemental type is vitally connected with one or more of the many elements. The main ones being air, earth, fire, or water
  • Fey: Fey are creatures of innate magic and with a strong connection to nature. Often they are connected to the Feywild.
  • Fiends: Cursed creatures that originate from the Negative Realms. Many are inherently evil, but not all of them.
  • Godly: Literal Gods. These types are usually very powerful creatures of Tier 6 or Tier 7.
  • Humanoid: Humanoid is a biped creature with a culture.
  • Monstrosity: Many times a creature of a magical origin, a curse or even unknown origins.
  • Ooze: Gelatinous creatures that resemble giant macroscopic bacterias.
  • Plant: Plants include both vegetable and fungal creatures.
  • Undead: Undead creatures were once alive, but reanimated by unnatural forces.

Size

Different creatures have different sizes. There are a total of 7 sizes a creature can have as shown in the Size Table.

Size Table
Size Space Occupies
Tiny
2 feet by 2 feet or less
Small
5 feet by 5 feet
Medium
5 feet by 5 feet
Large
10 feet by 10 feet
Enormous
15 feet by 15 feet to 20 feet by 20 feet
Gigantic
25 feet by 25 feet to 45 feet by 45 feet
Colossal
50 feet by 50 feet or more

Size can greatly affect an encounter, as many effects are dependent on the size of a creature. Typically, larger creatures are harder to deal with, as they can avoid many effects such as being grappled.

XP

When the creature is defeated, you can then reward your players with XP. You determine the XP by the following way:

  • Tier multiplied by Challenge Points

For example, a Tier 4 creature with 10 Challenge Points would yield 40 XP when defeated.

Special Loot

Some monsters may drop special loot upon defeat, such as unique equipment, armor, weapons, or consumables.

This loot can be specific to the monster, its culture or race, or can be harvested from the monster itself. It is important to consider whether or not a monster should have special loot, and only include it if it makes sense for the monster to possess something unique.

Armor Class (AC)

All creatures have an Armor Class (in short AC), which represents the difficulty to hit the creature with Attacks.

When you make an Attack, roll a d20 and add the skill bonus required for the Attack. If the result is equal or higher than the AC of the target you attacked, you hit the Attack. If the result is lower, you miss the Attack and deal no damage.

Armor Power (AP)

A creature wearing good armor gains extra protection.

Before they receive any slash, strike or thrust damages, they reduce the damage by their AP first

Example: If a creature has 3 AP and takes 10 Slash damage, the damage is reduced by 3 to a total of 7.

You have this types of Armor:

No Armor

The AC while you’re not wearing armor is equal to 8 + your Agility bonus and the AP is 0.

Light Armors

Light Armors are great for creatures that are naturally agile and able to easily evade attacks.

However, Light Armors don’t offer that much protection power, so they usually have 0 or 1 AP. The AC of Light Armors are defined by a fixed number + your Agility bonus to a maximum bonus of +10.

Light Armor Table
Armor Type AC AP Material
Padded Armor
9 + Agility (Max +10)
1
Leather
Leather Armor
10 + Agility (Max +10)
Leather
Brigandine Armor
10 + Agility (Max +10)
1
Leather
Chain Shirt
10 + Agility (Max +10)
1
Metal

Medium Armors

Medium Armors are great for creatures that are not either incredibly agile nor incredibly strong. They are balanced and offer some of the benefits of Light Armors and Heavy Armors.

The AP is determined by each type of Medium Armor. Most Medium Armors have an AP of 1 or 2. The AC of Medium Armors are defined by a fixed number + your Agility bonus to a maximum of a +2 or +4 bonus.

Medium Armor Table
Armor Type AC AP Material
Hide Armor
12 + Agility (Max +4)
1
Leather
Chain Mail
14 + Agility (Max +4)
1
Metal
Scale Mail
12 + Agility (Max +2)
2
Metal
Breastplate
14 + Agility (Max +2)
2
Metal

Heavy Armors

Heavy Armors are great for creatures that are strong enough to wear them. They offer great protection, but at the same time they make a creature less agile.

Heavy Armors impose a penalty on the Dexterity stat (minimum stat is -5) and also require a minimum Athletics bonus to be used, as shown in the Athletics Needed and Dex Penalty columns in the Heavy armor Table respectively. Wearing Heavy Armors while you don’t have the required Athletics bonus, makes you become Contained.

Heavy Armor offers great protection, so they usually have an AP of 2 or 3. The AC of Heavy Armors are defined by a fixed number, which usually varies from 16 to 18.

Heavy Armor Table
Armor Type AC AP Dex Penalty Material
Banded Mail
16
2
-1
Leather
Half Plate
17
2
-1
Metal
Splint Mail
17
3
-2
Metal
Full Plate
18
3
-2
Metal

Natural Armor

Some monsters have natural armor, which can give them any AC or AP without following these armor traits. These tables serve only as a guideline when building your own monster.

Posture / HP

All creatures have Posture and Health Points (HP), which represent their total capacity to remain in a fight.

When your character takes damage, you first reduce its Posture by the amount of damage it took. While Posture is being used, your character is not being wounded. It is just evading attacks which drains its energies.

Once the Posture is reduced to 0, you then start to reduce the HP. Any excess damage you take after your Posture is reduced to 0 is subtracted by your HP.

Once your HP is being drained, it means that your character is being wounded.

Keep in mind that Bleed, Brain and Poison damages ignore your Posture, directly reducing your HP.

Defining your Posture

All creatures have a Maximum Posture that they can have at once. 

In case of monster, their Sturdiness grants a different amount of Maximum Posture per Challenge Point. A Fragile monster gains 2 Max Posture per Challenge Point, while a Sturdy monster gains 4 Max Posture per Challenge Point for example. After you define your Posture from Challenge, you add the monster’s Reflex bonus to your Max Posture.

Example: My monster is Sturdy and has 3 Challenge Points and a Reflex bonus of +3. In this case, they would have 15 Posture (4 + 4 + 4 + 3).

Once you finish a Short or Long rest, you completely replenish your Posture.

If your Posture is reduced to 0, all creatures can also make a Melee Attack of Opportunity against you if possible.

Keep in mind that Bleed, Brain and Poison damages ignore your Posture, directly reducing your HP.

Defining your HP

All creatures have a Maximum HP that they can have at once. 

In case of monster, their Sturdiness grants a different amount of Maximum HP per Challenge Point. A Fragile monster gains 4 Max HP per Challenge Point, while a Sturdy monster gains 8 Max HP per Challenge Point for example. After you define your HP from Challenge, you add the monster’s Endurance bonus to your Max HP.

Example: My monster is Sturdy and has 3 Challenge Points and a Endurance bonus of +7. In this case, they would have 31 HP (8 + 8 + 8 + 7).

You only replenish your HP when you finish a Full rest.

Monster HP & Posture
Monster Sturdiness HP/ Posture per Challenge Point
Very Fragile
2 HP / 1 Posture
Fragile
4 HP / 2 Posture
Medium
6 HP / 3 Posture
Sturdy
8 HP / 4 Posture
Very Sturdy
10 HP / 5 Posture

Immunities, Resistances, Weaknesses

Damage Immunity

A creature that is immune takes 0 damage from that type.

Damage Resistance

A creature with resistance takes half the damage (rounded down) from that damage type.

Damage Weakness

A creature with weakness doubles the damage from that type

Damage Interactions

Damage resistance or weakness is always calculated last. First, you subtract the AP from the damage, and then you apply effects that halve or double the damage.

Resistance and weakness do not stack. If you gain two resistances to the same type of damage, you are affected by only one of those effects. The same applies to weakness.

However, resistance and weakness cancel each other out. If you gain resistance to one type of damage, but then some other effect imposes weakness to that same type of damage, they cancel each other, resulting in normal damage.

Immunity is not affected by weakness. If some effect imposes weakness to a type of damage you are immune to, you will still take 0 damage from it.

There are a total of 15 types of damage, each fitting in one specific category. The damage types and categories are as shown in the list below. 

Physical Damage
  • Slash Damage
  • Strike Damage
  • Thrust Damage
Elemental Damage
  • Fire Damage
  • Electric Damage
  • Cold Damage
Magical Damage
  • Dark Damage
  • Force Damage
  • Light Damage
Uncommon Damages
  • Acid Damage
  • Sonic Damage
  • Psychic Damage
Posture-Bypassing Damage
  • Bleed Damage
  • Brain Damage
  • Poison Damage

It is important to think if the monster has Immunity, Resistance or Weakness to any of these damage types.

For example a skeleton is Immune to Brain, Bleed, Poison and Psychic damage, and also has Resistance to Thrust damage. However, it is also Weak against Strike damage.

Passive Perception & Passive Insight

Your Passive Perception is equal to 10 + your Perception skill. Your Passive Insight is equal to 10 + your Insight skill.

Senses

A monster can have one or more types of senses. 

  • Dark Vision: The creature can see in the dark and is not partially or completely blinded in dark places. While doing so, it cannot see any colors, except for black and white.
  • Blind Sense: The creature is immune to being partially or completely blinded. It can manifest as tremor sense, sonar, wave sense, magic, and others.
  • Ethereal Vision: The creature is able to perceive things in the Ethereal dimension. This can include ghosts and other immaterial creatures.
  • True Vision: The creature can see through any visual effect and can discern any sound effect made by an illusion.

Language

Choose the languages that would be appropriate for your monsters. Some monsters don’t speak as well.

Language List
Standard Languages Alphabet
Common
Common
Dwarvish
Dwarvish
Elvish
Sylvan
Goblish
Orcish
Gnomish
Sylvan
Halfic
Dwarvish
Jotun
Elemental
Orcish
Orcish
Exotic Languages Alphabet
Abyssal Speech
None
Celestial Speech
Divine
Dark Common
Common
Draconic
Draconic
Elemental Speech
(Aquan, Auran, Ignan, Terran)
Elemental
Infernal Speech
Divine
Sylvan
Sylvan
Special Languages Special Trait
Braille
This is a written language that Blind creatures can read through touch.
Far Speech
This is a language that causes insanity for those who hear and understand it. It manifests itself through dreams and hallucinations.
Druidic
This is the primordial language of nature, which magically uses sounds, sight, smells and tastes to communicate vague ideas.
Sign Language
Deaf creatures can still understand this language, and you produce no sound with it
Thieves' cant
These are symbols and cryptic messages that vary from region to region. Only those who know them can understand

Movement

There are 3 types of Movement:

  • Base Speed
  • Secondary Speeds
  • Dash Speed

Base Speed

The Walking Speed is always considered your character Base speed. Some races and abilities grant you access to other types of speed to be considered your base speed. Your Base speed is defined by your Agility skill as shown in the Base Speed Table.

Base Speed Table
Agility Bonus Base Speed
-4 or -5
15 feet
-3 or -2
20 feet
-1 to +1
25 feet
+2 to +4
30 feet
+5 to +7
35 feet
+8 to +10
45 feet
+11 or more
60 feet

Secondary Speeds

Some other types of creatures, such as fishes or birds, have other base speeds instead of walking speed. Fishes have the Swimming speed as their Base speed, and birds have the Flying speed as their base speed, for example.

If a creature has the Swimming speed as their Base speed, instead of using its Athletics skill to determine its Swimming speed, that creature would use its Agility skill to determine its swimming speed.

If a creature does not have a walking speed, it means it can’t move while on the ground.

You can always include different types of speed to be the secondary speed of your monster.

You can also include the Walk speed in here, in which case it will no longer be that creature Base Speed.

Athletics Bonus Climbing / Swimming Speed
-4 or -5
Your too frail to climb or swim
-3 or -2
5 feet
-1 to +1
10 feet
+2 to +4
15 feet
+5 to +7
20 feet
+8 to +10
25 feet
+11 or more
30 feet

Dash Speed

During your turn, you can use your Bonus Action to Dash. When you Dash, you add your Dash speed to your Base speed until the end of your turn. However, after Dashing, you can only move in one direction until the end of your turn.

Note that when you Dash, it only increases your Base speed. If your current terrain is underwater and your Base speed is not your Swimming speed, your Dash won’t increase your Swimming speed.

Your Dash speed is determined by your Athletics skill as shown in the Dash Speed Table.

Dash Speed Table
Athletics Bonus Dash Speed
-4 or -5
Your too frail to dash
-3 or -2
10 feet
-1 to +1
20 feet
+2 to +4
30 feet
+5 to +7
40 feet
+8 to +10
50 feet
+11 or more
60 feet

Example of a Sheet

Want to edit the sheet?

You can use GMbinder to edit all the details of the sheet.

You can find the link here.

Abilities & other Actions

Once you have defined the Attributes of your monster, it is now time to define the abilities and actions of your monster.

But first what are the Actions your monster can have? Here is a list of everything your monster can have:

  • Villain Actions: They are a special type of action that only certain monsters have. They give more flavor to the battle and can be used anytime during combat.

  • Actions: Attack, Dodge, Grapple, Hide, Hold Action, Use Environment/ Object

  • Bonus Actions: Dash,Disengage,Shove, Mount/Dismount

  • Reaction: Attacks of Opportunity, Use Shields

  • Free Action: Switch Shield or Weapons, Influence

  • Abilities: Passive abilities that your monster always has.

When deciding about your monster abilities and the power of their attacks, you should ask yourself these 3 questions:

  • What’s your monster Tier & Challenge Points?
  • What is the main Gimmick of it?
  • Is it Balanced?

What's your Monster Tier & Challenge Points?

The Tier of your monster greatly affects how powerful and complex it can be.

A Tier 1 monster should be simpler for players at lower levels, as they have fewer abilities to counter certain attacks. Conversely, a Tier 5 monster should have more abilities and attacks, as players at higher levels will need a bigger challenge. Monsters with higher Challenge Points will also have more HP and deal more damage than creatures with lower Challenge Points.

What is the main Gimmick of it?

The Gimmick of your monster should be reflected by their actions and abilities. Let’s use the Giant Mosquito as an example to show this gimmick.

A Giant Mosquito is known for sucking blood. So giving an Attack that causes Bleeding and an ability such as Bloody Frenzy (which gives them an extra Attack against a creature that is Bleeding) is a perfect way to reflect their blood sucking gimmick.

A Mosquito is also hard to catch. So giving them Evade to make them harder to hit would also make perfect sense.

A Mosquito is also very fragile and easy to kill once you hit him. So making them very fragile when deciding their Posture and HP would also make good sense.

With all of those things combined, you can really sell the idea that your players are fighting an annoying mosquito, and really make the gimmick of the monster shine.

Is it Balanced?

Once you have made your monster, you should ask yourself if it is balanced. Is it possible to defeat him? Is it possible for them to one shot a character during their turn? What are their strengths and weaknesses?

The damage your monster can deal each turn is a great way to measure how powerful it actually is. However, there are a few traps when measuring damage this way:

  • Number of Attacks
  • Critical Hits, Fails and Luck
  • How Sturdy it is
  • Abilities must always be considered

Number of Attacks

The number of Attacks your monster makes is extremely important. A monster that makes only 1 Attack that is super strong has a different feel than a monster that makes multiple weaker Attacks.

The higher the number of Attacks, the more consistent their damage will be as well, but if that one strong Attack hits, its gonna hurt…

Multiple Attacks can be distributed among player (or maybe not), but 1 strong can is going to really hurt 1 player.

There is 2 other important things to consider:

Number of Attacks & Conditions

The higher the number os Attacks, the more Saves the players must do.

If an Attack imposes a Condition (Bleeding, Poison, etc.) having the monster make multiple Attacks, will make the players more likely to fail.

These types of Attacks can slow down the game, so they should’t be used on monster that are meant to be used on large numbers, like minions.

Number of Attacks & AP

The more Attacks your monster makes, the weaker it actually becomes against creature with AP.

Consider a creature that makes three attacks per turn, with each attack dealing 1d6 damage. Now, imagine another creature that only makes one attack per turn, but each attack deals 3d6 damage.

At first glance, it might seem like both creatures deal the same amount of damage. However, things can change depending on the circumstances. What if the attack dealt slashing damage and was used against a creature with 3 AP?

In this case, the first creature would only deal damage equal to 3d6-9, since each of its three attacks would be reduced by the armor. On the other hand, the second creature would deal 3d6-3 damage, since the armor would only reduce the damage once.

In the end, the creature that attacks only once deals 6 more damage than the one that attacks three times. AP can play a significant role in combat and can severely weaken creatures that make multiple attacks per turn.

 

Critical Hits, Fails, and Luck

Making multiple Attacks per turn might be weaker because of the AP, but it also has other huge advantages. The main one being that it also increases the chances of Critical Hits.

For this reason, it is very important to consider the Luck stat when building your monster, since each Critical Hit deals 1d6 + your Luck damage.

Giving a negative Luck stat to your monster can counterbalance this advantage of multiple Attacks per turn. It can even become a disadvantage because you can also increase the Critical Fail rate of your monster.

A creature with -2 Luck would score Critical Fails on rolls of 1 or 2. If that creature Attacks multiple times per turn on top of that, the chances of it scoring a Critical Fail become incredibly high.

On the other hand, you can also choose to give a positive Luck stat, increasing the power of your monster multiple Attacks even further.

A positive Luck stat can also grant your monster Luck Points to use against your players, further enhancing its multiple Attacks.

How sturdy it is

Remember the HP and Posture Guide table for your monster? Well, let’s use it again:

Monster Sturdiness HP/ Posture per Challenge Point
Very Fragile
2 HP / 1 Posture
Fragile
4 HP / 2 Posture
Medium
6 HP / 3 Posture
Sturdy
8 HP / 4 Posture
Very Sturdy
10 HP / 5 Posture

It is very important to consider how sturdy your monster is when deciding how deadly it is.

Fragile monsters tend to deal more damage, since they lean towards a faster combat style. A more sturdy monster tends to deal less damage, since they lean towards a slower combat style.

There are always exceptions, but this is a good rule of thumb that you can use when building your monster.

Abilities must always be considered

With all of that being said, some abilities can simply ignore everything that we just said now.

A great example of this is the Giant Bee. That creature simply deals an insane amount of damage that is much higher than any other creature in its Tier.

However, the Giant Bee has an ability called kamikaze that counterbalances that. After the Giant Bee hits an Attack, it then simply dies right after.

Abilities can be very tricky, so it’s up to your intuition to implement them when building your own monster.

Save or Suck

Some abilities are known as ‘Save or Suck.’ These are high-risk, high-reward abilities that pose a significant threat on a failure but are mostly harmless on a success.

Use these abilities wisely, and avoid going to extremes with them.

It’s also advisable to give hints to the players before combat and to make the ability known beforehand, giving the players a chance to prepare themselves.

Excess of Abilities

When creating a monster, it is important to consider the flow of combat. Making a monster that on paper is balanced is easy. However, if the creature has too many Saves, too many abilities or too many cluncky mechanics, it can make the combat feel bad.

Monsters with a lot of abilities are usually reserved for Tier 4 – 6 Boss monsters, when the game complexity increases and the GM has more experience dealing with combat.

Improvisation

When you create a homebrew monster, you are acting like a designer. Most of the time, its going to be the first time you are using this monster. Mistakes can happen. You should improvise when you make a mistake, not when the player outsmart you in any way.

Don’t be afraid to adjust the monster on the spot. Keep in mind that keeping the game fun is the highest priority!

Maybe the ability was too strong, so you can say that the monster can only use it just once. Maybe it had too many Attacks or abilities, so after being hurt, it loses some Attacks or abilities. Maybe it was too tanky, so you can adjust the HP on the spot.

Damage Per Turn Guide

With all of those things said, here is a list to show how deadly each amount of damage can be depending on your Tier:

Tier 1
Danger Average Damage per Turn
Low
1 - 3
Considerable
4 - 5
High
6 - 7
Very High
8 - 9
Deadly
10+
Tier 2
Danger Average Damage per Turn
Low
8-10
Considerable
11-15
High
16-20
Very High
20-29
Deadly
30+
Tier 3
Danger Average Damage per Turn
Low
11 - 15
Considerable
16 - 24
High
25 - 40
Very High
41 - 49
Deadly
50+
Tier 4
Danger Average Damage per Turn
Low
16 - 24
Considerable
25 - 40
High
41 - 60
Very High
61 - 79
Deadly
80+
Tier 5
Danger Average Damage per Turn
Low
25 - 40
Considerable
41 - 60
High
61 - 79
Very High
80 - 99
Deadly
100+
Tier 6
Danger Average Damage per Turn
Low
41 - 59
Considerable
60 - 70
High
71 - 90
Very High
91 - 119
Deadly
120+

What damage should I use?

Monsters with higher Challenge Points should often deal High or Very High damage to represent a greater challenge, while those with lower challenge points should deal a Considerable or Low amount of damage.

Creatures with powerful abilities should also deal Low damage to compensate for their abilities.