Home >Bestiary >Rules for Monsters >

Monster Creation



Creating a monster is part science and part art. While most monsters follow a general pattern of their overall power and abilities as related to their Challenge Rating (CR), there are many exceptions. Some monsters, for example, have significantly more hit points or a higher AC than the average for their CR, but make up for this advantage by being weak in other areas. Other monsters have significantly higher average damage, but have a lower attack bonus.

Building the Monster

The following guidelines are provided to assist in monster creation and to help balance a creation for its CR.

Step 1: Concept

The first step in creating a new monster is to define its concept and role in the game. Generally, this involves picking the monster’s CR, type, physical appearance, and manner of fighting. Once you have these basic pieces of information, you should find a number of similar monsters of the same type and roughly the same CR for comparison purposes.

Step 2: Target Statistics

Once you have a creature’s type and CR determined, use Table: Monster Statistics by CR to determine its approximate statistics by CR. These values are a rough guideline only. You will notice that many of the existing monsters do not follow these guidelines exactly. Most monsters excel in one of these areas, usually in the amount of damage dealt, but lag in one or two other areas to help balance them out.

Table: Monster Statistics by CR
CR Hit Points Armor Class High Attack Low Attack Average Damage Primary
Ability DC
Secondary
Ability DC
Good
Save
Poor
Save
High Low
1/2 10 11 1 0 4 3 11 8 3 0
1 15 12 2 1 7 5 12 9 4 1
2 20 14 4 3 10 7 13 9 5 1
3 30 15 6 4 13 9 14 10 6 2
4 40 17 8 6 16 12 15 10 7 3
5 55 18 10 7 20 15 15 11 8 4
6 70 19 12 8 25 18 16 11 9 5
7 85 20 13 10 30 22 17 12 10 6
8 100 21 15 11 35 26 18 12 11 7
9 115 23 17 12 40 30 18 13 12 8
10 130 24 18 13 45 33 19 13 13 9
11 145 25 19 14 50 37 20 14 14 10
12 160 27 21 15 55 41 21 15 15 11
13 180 28 22 16 60 45 21 15 16 12
14 200 29 23 17 65 48 22 16 17 12
15 220 30 24 18 70 52 23 16 18 13
16 240 31 26 19 80 60 24 17 19 14
17 270 32 27 20 90 67 24 18 20 15
18 300 33 28 21 100 75 25 18 20 16
19 330 34 29 22 110 82 26 19 21 16
20 370 36 30 23 120 90 27 20 22 17
21 400 37 31 24 130 98 27 20 23 18
22 400 39 32 25 140 105 28 21 23 18
23 480 40 33 26 150 113 29 22 24 19
24 520 42 35 27 165 124 30 23 25 20
25 560 43 36 28 180 135 30 24 26 21
26 600 44 37 29 195 145 31 25 27 22
27 640 45 38 30 210 155 32 26 28 23
28 680 46 39 31 225 165 33 27 29 24
29 720 47 40 32 240 175 34 28 30 25
30 760 48 41 33 255 185 35 29 31 26

When referring to Table: Monster Statistics by CR, keep the following points in mind.

CR: This is the approximate CR of the monster. This number might change as design progresses.

Hit Points: This is the approximate hit point total for the monster. Note that creatures with particularly high armor classes or saving throws, or a number of resistances, might have a lower number. Outsiders and constructs typically have lower hit point totals.

Armor Class: This is the average armor class for a creature of this CR. When it comes time to design the creature’s protections, keep this number in mind. Creatures with Hit Points above the average often have lower armor class values to compensate.

High Attack: This is the average total attack bonus for a creature of this CR. This value is for creatures that are primarily melee or ranged combatants. Creatures with a higher than normal average damage typically have a lower attack value to compensate.

Table: Average Die Results
Die Type Average Result*
d4 2.5
d6 3.5
d8 4.5
d10 5.5
d12 6.5
d20 10.5

* Always round down after multiplying. For example, treat the average of 1d4 as 2, and the average of 2d4 as 5.

Low Attack: This is the average total attack bonus for a creature of this CR that does not rely upon melee or ranged attacks to deal damage. This includes most creatures that rely on spells and spell-like abilities in combat.

Average Damage: This is the average amount of damage dealt by a creature of this CR if all of its attacks are successful. To determine a creature’s average damage, add the average value for all of the damage dice rolled (as determined by Table: Average Die Results) to the damage modifier for each attack.

A creature that relies on melee or ranged weapons in combat should have average damage within the range of high and low damage.

A creature with higher than normal attack bonuses will often deal lower damage, while a creature with lower than normal attack bonuses will often deal higher damage.

Primary Ability DC: This is the average difficulty class (DC) for any spells, spell-like abilities, and special abilities (such as breath weapons) possessed by a creature of this CR that relies on such attacks in combat. If an ability is particularly powerful, it might have a lower DC to compensate.

Secondary Ability DC: This is the average DC for spells and special abilities for a creature that does not rely on such attacks in combat. Generally, a DC should not be lower than this number.

Good Save: This is the average saving throw bonus for a creature of this CR if the saving throw is one of the creature’s good saving throws.

Poor Save: This is the average saving throw bonus for a creature of this CR if the saving throw is one of the creature’s poor saving throws.

Step 3: Hit Dice

The next step in creating a monster is to determine the approximate number of Hit Dice it has. Hit Dice determine a wide variety of other statistics, including the creature’s feats, skills, Hit Points, attack bonuses, and special ability DCs.

Table: Creature Hit Dice
Creature Type Challenge Rating
1/2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Aberration 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Animal 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Construct 1 2 3 4 5 6 8 9 10 12 13 14 16 18 19 20 21 23 25 28 31
Dragon 1 2 3 4 5 6 7 8 9 11 12 13 14 16 17 18 19 21 23 25 29
Fey 2 3 4 5 6 8 10 12 13 15 17 18 20 22 23 25 26 28 31 33 37
Humanoid 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Magical beast 1 2 3 4 5 6 8 9 10 12 13 14 16 18 19 20 21 23 25 28 31
Monstrous humanoid 1 2 3 4 5 6 8 9 10 12 13 14 16 18 19 20 21 23 25 28 31
Ooze 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Outsider 1 2 3 4 5 6 8 9 10 12 13 14 16 18 19 20 21 23 25 28 31
Plant 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Undead 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 34
Vermin 1 2 3 4 5 7 9 10 12 14 15 16 17 19 20 22 24 26 28 30 32

A creature’s total number of Hit Dice depends on a number of factors, but the two most important are its CR and its type. Table: Creature Hit Dice lists the average number of Hit Dice for each creature type, depending on its CR. While many of the monsters are close to these values, some are not. This is because they have higher or lower average Hit Points to balance out their armor class or resistances.

Step 4: Size

Table: Size
Size Minimum CR Maximum CR Base Str Base Dex Base Con
Fine 2 1 18 8
Diminutive 4 1 16 8
Tiny 6 2 14 8
Small 6 12 8
Medium 10 10 10
Large 2 18 8 14
Huge 4 26 6 18
Gargantuan 6 34 6 22
Colossal 8 42 6 26

Now that you have the creature’s average statistics, it’s time to pick its size. Most creatures range in size from Small to Huge, but other sizes are not uncommon. A creature’s size sets a baseline for its physical ability scores and its natural weapon damage (as noted in the Natural Attacks description in the Universal Monster Rules). You should pick a size that fits well with the creature’s intended role in the game and Challenge Rating. If you decide to give a creature an unusual size for its CR or HD, you should justify the unusual choice in the monster’s description to account for the discrepancy—in most cases, such unusually sized monsters should be highly magical in nature. See Table: Size for more information on creature sizes and expected scores.

Minimum/Maximum CR: These values list the minimum and the maximum challenge ratings a creature of the indicated size should fall between.

Base Str, Base Dex, Base Con: These list the average scores for a creature of this size. Your specific monster’s Strength, Dexterity, or Constitution might vary greatly from these numbers, but if they do, you should pay close attention to how these variances affect its other statistics.

Step 5: Abilities

Once you have determined a creature’s size, type, and Hit Dice, it’s time to move on to its ability scores. The bonuses granted from these ability scores should increase a creature’s hit points, attack bonuses, and saving throws to the approximate values presented on Table: Monster Statistics by CR.

A creature’s physical ability scores (Strength, Dexterity, and Constitution) should be relatively close to the base values presented on Table: Size, depending on its size. Creatures with a few Hit Dice but a high average hit point total should have a higher than normal Constitution.

A creature’s mental ability scores (Intelligence, Wisdom, and Charisma) are largely defined by the creature’s concept. The base for all of these abilities is 10. Creatures that rely on spells and spell-like abilities in combat should have one mental ability score that stands out (usually Charisma). Creatures incapable of speech have an Intelligence score of 2 or lower. Unintelligent undead, constructs, oozes, plants, and vermin rarely have an Intelligence score.

Step 6: Skills and Feats

Using Table: Creature Statistics by Type, determine how many skill ranks your creature has based on its type and Hit Dice. Assign these ranks as determined by the creature’s concept. A creature’s class skills are determined by its type (see creature types). Creatures with a low Intelligence typically only have ranks in Dexterity– and Strength-based skills.

Table: Creature Statistics by Type
Type Hit Die Base Attack Bonus (BAB) Good Saving Throws Skill Ranks* Class Skills
Aberration d8 HD × 3/4 (Medium BAB) Will 4 + Int mod per HD Acrobatics, Climb, Escape Artist, Fly, Intimidate, Knowledge (pick one), Perception, Spellcraft, Stealth, Survival, and Swim.
Animal d8 HD × 3/4 (Medium BAB) Fort, Ref 2 + Int mod per HD Acrobatics, Climb, Fly, Perception, Stealth, and Swim.
Construct d10 HD (Fast BAB) 2 + Int mod per HD None
Dragon d12 HD (Fast BAB) Fort, Ref, Will 6 + Int mod per HD Appraise, Bluff, Climb, Craft, Diplomacy, Fly, Heal, Intimidate, Knowledge (all), Linguistics, Perception, Sense Motive, Spellcraft, Stealth, Survival, Swim, and Use Magic Device.
Fey d6 HD × 1/2 (Slow BAB) Ref, Will 6 + Int mod per HD Acrobatics, Bluff, Climb, Craft, Diplomacy, Disguise, Escape Artist, Fly, Knowledge (geography), Knowledge (local), Knowledge (nature), Perception, Perform, Sense Motive, Sleight of Hand, Stealth, Swim, Use Magic Device.
Humanoid d8 HD × 3/4 (Medium BAB) Varies (any one) 2 + Int mod per HD Climb, Craft, Handle Animal, Heal, Profession, Ride, and Survival (plus any gained from class levels.)
Magical beast d10 HD (Fast BAB) Fort, Ref 2 + Int mod per HD Acrobatics, Climb, Fly, Perception, Stealth, Swim.
Monstrous humanoid d10 HD (Fast BAB) Ref, Will 4 + Int mod per HD Climb, Craft, Fly, Intimidate, Perception, Ride, Stealth, Survival, and Swim.
Ooze d8 HD × 3/4 (Medium BAB) 2 + Int mod per HD None
Outsider d10 HD (Fast BAB) Varies (any two) 6 + Int mod per HD Bluff, Craft, Knowledge (planes), Perception, Sense Motive, and Stealth (plus 4 additional.)
Plant d8 HD × 3/4 (Medium BAB) Fort 2 + Int mod per HD Perception and Stealth.
Undead d8 HD × 3/4 (Medium BAB) Will 4 + Int mod per HD Climb, Disguise, Fly, Intimidate, Knowledge (arcana), Knowledge (religion), Perception, Sense Motive, Spellcraft, and Stealth.
Vermin d8 HD × 3/4 (Medium BAB) Fort 2 + Int mod per HD None