Rules Index | GM Screen


Bestiary

Source Pathfinder RPG Bestiary pg. 5
Welcome to the Pathfinder Roleplaying Game Bestiary! Within the pages of this tome you will encounter a wide range of monsters and creatures to pit against your players as they explore your world. The creatures featured herein have been drawn from a wide range of sources, from real-world legends and myths (where we get our dragons and demons, our basilisks and yetis), to the traditions of the RPG’s rich history (such as the shambling mound and the rust monster), to the inventions of writers both old (such as H. G. Wells’s morlocks or H. P. Lovecraft’s ghasts and shoggoths) and new. In order to fully use the creatures in the Pathfinder RPG Bestiary, you’ll need a copy of the Pathfinder Roleplaying Game Core Rulebook. These two books comprise the core rules for the Pathfinder RPG.

While each monster is a unique creature, many possess similar special attacks, defenses, and qualities. Unique abilities are described below the monster’s stat block. Many abilities common to several monsters appear in the universal monster rules. If a monster’s listed special ability does not appear in its description, you’ll find it there.

This book’s appendices also contain a wealth of other information—you’ll find rules for altering a monster’s stats (including making it more or less powerful by applying templates, adjusting size and Hit Dice, or even giving a monster class levels), guidelines for monstrous PCs, and more.

Each monster description on the following pages is presented in the same format, split into three specific areas: Introduction, Stat Block, and Description.

Introduction

Source Pathfinder RPG Bestiary pg. 5
Each monster is presented alphabetically. In the case of a group of monsters sharing similar traits (such as outsider races and some animals or vermin), the monster’s basic name is listed first.

Stat Block

Source Pathfinder RPG Bestiary pg. 5
This is where you’ll find all of the information you need to run the monster in an encounter. A stat block is organized as follows. Note that in cases where a line in a stat block has no value, that line is omitted.

Name and CR: The monster’s name is presented first, along with its challenge rating (CR) and three icons you can use to quickly identify the creature’s role in the game. Challenge rating is a numerical indication of how dangerous a monster is—the higher the number, the deadlier the creature. Challenge rating is detailed on page in the Desigining Encounters section.

XP: Listed here are the total experience points that PCs earn for defeating the monster.

Race, Class, and Level: Some monsters do not possess racial Hit Dice and are instead defined by their class levels. For these monsters, their race, class, and level appear here. Unless otherwise noted, the first class listed is the class chosen by the monster as its favored class.

Alignment, Size, and Type: While a monster’s size and type remain constant (unless changed by the application of templates or other unusual modifiers), alignment is far more fluid. The alignments listed for each monster in this book represent the norm for those monsters—they can vary as you require them to in order to serve the needs of your campaign. Only in the case of relatively unintelligent monsters (creatures with an Intelligence of 2 or lower are almost never anything other than neutral) and planar monsters (outsiders with alignments other than those listed are unusual and typically outcasts from their kind) is the listed alignment relatively unchangeable.

Init and Senses: The creature’s initiative modifier followed by any special senses and its Perception check modifier.

Aura: If the creature has a particular magical or exceptional aura, it is listed here along with its radius from the creature and, as applicable, a save DC to resist the aura’s effects.

AC: The creature’s Armor Class, touch Armor Class, and flat-footed Armor Class. The modifiers that generate its AC are listed parenthetically at the end of this entry.

hp: The creature’s hit points, followed by its Hit Dice (including modifiers from Constitution, favored class levels, creature type modifiers, and the Toughness feat). Creatures with PC class levels receive maximum hit points for their first HD, but all other HD rolls are assumed to be average. Fast healing and regeneration values, if any, follow the creature’s HD.

Saving Throws: The creature’s Fortitude, Reflex, and Will saves, followed by situational modifiers to those rolls.

Defensive Abilities/DR/Immune/Resist/SR: All of the creature’s unusual defensive abilities. Damage reduction, immunities, resistances, and spell resistance are called out separately as necessary.

Weaknesses: All of the creature’s unusual weaknesses are listed here.

Speed: The creature’s land speed, and additional speeds as necessary for the creature.

Melee: The creature’s melee attacks are listed here, with its attack roll modifier listed after the attack’s name followed by the damage in parentheses.

Ranged: As Melee above, but for ranged attacks.

Space/Reach: The creature’s space and reach—if the creature’s space and reach are standard (one 5-foot square and a reach of 5 feet), this line is omitted.

Special Attacks: The creature’s special attacks. Full details for these attacks are given at the end of the stat block or in the universal monster rules section.

Spell-Like Abilities: After listing the caster level of the creature’s spell-like abilities, this section lists all of the creature’s spell-like abilities, organized by how many times per day it can use the abilities. Constant spell-like abilities function at all times but can be dispelled. A creature can reactivate a constant spell-like ability as a swift action.

Spells Known/Prepared: If the creature can actually cast spells, its caster level is indicated here followed by the spells it knows or typically has prepared. Unless otherwise indicated, a spellcasting creature does not receive any of a spellcasting class’s other abilities, such as a cleric’s ability to spontaneously convert prepared spells to cure or inflict spells.

Ability Scores: The creature’s ability scores are listed here. Unless otherwise indicated, a creature’s ability scores represent the baseline of its racial modifiers applied to scores of 10 or 11. Creatures with NPC class levels have stats in the standard array (13, 12, 11, 10, 9, 8), while creatures with character class levels have the elite array (15, 14, 13, 12, 10, 8); in both cases, the creature’s ability score modifiers are listed at the end of its description.

Base Atk/CMB/CMD: These values give the creature’s base attack, its Combat Maneuver Bonus, and its Combat Maneuver Defense score.

Feats: The creature’s feats are listed here. A bonus feat is indicated with a superscript “B.”

Skills: The creature’s skills are listed here. Racial modifiers to skills are indicated at the end of this entry.

Languages: The languages most commonly spoken by the creature are listed here. For unusual creatures, you can swap out the languages known for other choices as needed. A creature with a higher-than-normal Intelligence score receives the appropriate number of bonus languages.

SQ: Any special qualities possessed by the creature.

Environment: The regions and climates in which the creature is typically encountered are listed here; these often present wider ranges than the icons at the top of the stat block indicate. In this case, the icon listed at the top of the stat block indicates the creature’s preferred terrain.

Organization: This lists how the creature is organized, including number ranges as appropriate.

Treasure: The exact value of the creature’s treasure depends on if you’re running a slow, medium, or fast game, as summarized on Table 12–5. In cases where a creature has specific magical gear assigned to it, the assumption is a medium game—if you play a fast or slow game, you’ll want to adjust the monster’s gear as appropriate. “Standard” treasure indicates the total value of the creature’s treasure is that of a CR equal to the average party level, as listed on Table 12–5. “Double” or “triple” treasure indicates the creature has double or triple this standard value. “Incidental” indicates the creature has half this standard value, and then only within the confines of its lair. “None” indicates that the creature normally has no treasure (as is typical for an unintelligent creature that has no real lair, although such creatures are often used to guard treasures of varying amounts). “NPC gear” indicates the monster has treasure as normal for an NPC of a level equal to the monster’s CR (see Table 14-9).

Special Abilities: Finally, any of the creature’s more unique special abilities are detailed in full here.

Description

Source Pathfinder RPG Bestiary pg. 6
Here you’ll find information on how the monster fits into the world, notes on its ecology and society, and other bits of useful lore and flavor that will help you breathe life into the creature when your PCs encounter it. Some monsters have additional sections that cover variant creatures, notes on using the monsters as PCs, methods of constructing the creature, and so on.

Monster Creation

Source Pathfinder RPG Bestiary pg. 290
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.

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

Step 1: Concept

Source Pathfinder RPG Bestiary pg. 290
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

Source Pathfinder RPG Bestiary pg. 290
Once you have a creature’s type and CR determined, use Table 1–1 to determine its approximate statistics by CR. These values are a rough guideline only. You will notice that many of the existing monsters in this book 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. When referring to Table 1–1, 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.

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 1–5) 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.

Table 1-1: Monster Statistics by CR

Average Damage
CRHit PointsArmr ClassHigh AttackLow AttackHighLowPrimary Ability DCSecondary Ability DCGood SavePoor Save
1/21011104311830
11512217512941
220144310713951
3301564139141062
44017861612151073
555181072015151184
670191282518161195
78520131030221712106
810021151135261812117
911523171240301813128
1013024181345331913139
11145251914503720141410
12160272115554121151511
13180282216604521151612
14200292317654822151712
15220302418705223161813
16240312619806024171914
17270322720906724182015
183003328211007525182016
193303429221108226192116
203703630231209027202217

Step 3: Hit Dice

Source Pathfinder RPG Bestiary pg. 290
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.

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 1–2 lists the average number of Hit Dice for each creature type, depending on its CR. While many of the monsters in this book 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.

Table 1-2: Creature Hit Dice

Challenge Rating
Creature Type1/21234567891011121314151617181920
Aberration12345791012141516171920222426283034
Animal12345791012141516171920222426283034
Construct1234568910121314161819202123252831
Dragon123456789111213141617181921232529
Fey234568101213151718202223252628313337
Humanoid12345791012141516171920222426283034
Magical Beast1234568910121314161819202123252831
Monstrous Humanoid1234568910121314161819202123252831
Ooze12345791012141516171920222426283034
Outsider1234568910121314161819202123252831
Plant12345791012141516171920222426283034
Undead12345791012141516171920222426283034
Vermin12345791012141516171920222426283032

Step 4: Size

Source Pathfinder RPG Bestiary pg. 290
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 1–3 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.

Table 1-3: Size

SizeMinimum CRMaximum CRBase StrBase DexBase Con
Fine21188
Diminutive31168
Tiny62148
Small6128
Medium101010
Large218814
Huge426618
Gargantuan634622
Colossal842626

Step 5: Abilities

Source Pathfinder RPG Bestiary pg. 291
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 1–1.

A creature’s physical ability scores (Strength, Dexterity, and Constitution) should be relatively close to the base values presented on Table 1–3, 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

Source Pathfinder RPG Bestiary pg. 292
Using Table 1–4, 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 the creature types). Creatures with a low Intelligence typically only have ranks in Dexterity- and Strength-based skills.

After you have assigned skills, it’s time to assign the creature’s feats. Each creature with an Intelligence score receives a number of feats equal to 1 + 1 per every 2 Hit Dice after the first (so, 1 at 1 HD, 2 at 3 HD, etc.). A creature must qualify to take a feat as normal. See Table 1–6 for a quick feat calculation chart.

Table 1-4: Creature Statistics by Type

TypeHit DieBase Attack Bonus (BAB)Good Saving ThrowsSkill Ranks*
Aberrationd8HD x 3/4 (Medium BAB)Will4 + Int mod per HD
Animald8HD x 3/4 (Medium BAB)Fort, Ref2 + Int mod per HD
Constructd10HD (Fast BAB)2 + Int mod per HD
Dragond12HD (Fast BAB)Fort, Ref, Will6 + Int mod per HD
Feyd6HD x 1/2 (Slow BAB)Ref, Will6 + Int mod per HD
Humanoidd8HD x 3/4 (Medium BAB)Varies (any one)2 + Int mod per HD
Magical Beastd10HD (Fast BAB)Fort, Ref2 + Int mod per HD
Monstrous Humanoidd10HD (Fast BAB)Ref, Will4 + Int mod per HD
Oozed8HD x 3/4 (Medium BAB)2 + Int mod per HD
Outsiderd10HD (Fast BAB)Varies (any two)6 + Int mod per HD
Plantd8HD x 3/4 (Medium BAB)Fort2 + Int mod per HD
Undeadd8HD x 3/4 (Medium BAB)Will4 + Int mod per HD
Vermind8HD x 3/4 (Medium BAB)Fort2 + Int mod per HD
* As long as a creature has an Intelligence of at least 1, it gains a minimum of 1 skill point per Hit Die. Creatures with an Intelligence score of “—” gain no skill points or feats.

Step 7: Other Statistics

Source Pathfinder RPG Bestiary pg. 292
Using Tables 1–1, 1–4, and 1–6, you can now determine many of the creature’s other statistics.

When building a creature’s Armor Class, start by adding armor, shield, and natural armor bonuses to its Dexterity modifier. If a creature does not wear armor, give it a tougher hide to get it near its average AC. Remember that creatures with higher hit point totals might have a lower Armor Class, whereas creatures with fewer hit points might have a higher Armor Class. If a creature’s Armor Class deviates from the average by more than 5 points, it might not be the right CR.

When determining a creature’s attack bonuses, refer to the guidelines from Table 1–1 based on the creature’s CR. If the bonus is too low, consider increasing the creature’s Strength or Dexterity, or increasing the amount of damage it deals to above the average. If the bonus is too high, consider decreasing the creature’s Strength or Dexterity, or decrease the amount of damage it deals. If this value is significantly different, and the creature is intended to rely on melee or ranged attacks, consider adjusting the creature’s CR.

Use Table 1–5 to determine the number of damage dice, combined with damage bonuses, that the creature needs to reach the average damage for its CR. The creature might need additional or more damaging attacks to approach the average. Remember that creatures that primarily deal damage with other abilities, such as spells, do not need to meet the average damage for their attacks. You can also use Table 1–5 to determine a creature’s average hit points. Remember that PC class levels provide the maximum number of hit points at 1st level.

Repeat this process for a creature’s saving throws. If the saving throws are too high, consider altering the ability scores on which they are based.

When determining a creature’s speed, first decide if it has any alternative modes of movement, such as burrow, climb, fly, or swim. Most Medium creatures have a base speed of 30 feet. Quadrupeds and Large creatures increase this by 10 feet each. Smaller creatures decrease this base speed by 10 feet. If a creature is particularly fast or slow, modify the base speed by 10 feet. Burrow and climb speeds are usually half a creature’s base speed, while flying speeds are roughly double. Remember to give a creature the appropriate skills for any unusual movement methods.

Table 1-5: Average Die Results

Die TypeAverage Result*
d42.5
d63.5
d84.5
d105.5
d126.5
d1210.5


Table 1-6: Statistics Summary

HDFast BABMedium BABSlow BABGood SaveBad SaveFeats
1+1+0+0+2+01
2+2+1+1+3+01
3+3+2+1+3+12
4+4+3+2+4+12
5+5+3+2+4+13
6+6+4+3+5+23
7+7+5+3+5+24
8+8+6+4+6+24
9+9+6+4+6+35
10+10+7+5+7+35
11+11+8+5+7+36
12+12+9+6+8+46
13+13+9+6+8+47
14+14+10+7+9+47
15+15+11+7+9+58
16+16+12+8+10+58
17+17+12+8+10+59
18+18+13+9+11+69
19+19+14+9+11+610
20+20+15+10+12+610
21+21+15+10+12+711
22+22+16+11+13+711
23+23+17+11+13+712
24+24+18+12+14+812
25+25+18+12+14+813
26+26+19+13+15+813
27+27+19+13+15+914
28+28+20+14+16+914
29+29+21+14+16+915
30+30+22+15+17+1015

Step 8: Special Abilities and Qualities

Source Pathfinder RPG Bestiary pg. 292
Monsters are different from characters in that they can have all sorts of different special abilities and qualities. Each of these is tied closely to the creature’s concept, allowing it to fill a specific role in the game. For examples, look at monsters in this book. Monsters should use abilities from the Universal Monster Rules whenever possible, instead of creating new yet similar abilities—when you do create new abilities, use the Universal Monster Rules as a template for how to present and create the new abilities.

Most special abilities that cause damage, such as breath weapons, give a save (Fortitude, Reflex, or Will depending on the ability). The DC for almost all special abilities is equal to 10 + 1/2 the creature’s Hit Dice + a relevant ability modifier (usually Constitution or Charisma depending on the ability). Special abilities that add to melee and ranged attacks generally do not allow a save, as they rely on the attacks hitting to be useful.

Special senses and resistances to certain energy types are common in creatures of CR 5 and lower. Damage reduction, energy immunities, and regeneration are more common in creatures above CR 5. Spell resistance and immunities become more common above CR 10. As a general rule a creature’s spell resitance should equal its CR + 11.

Step 9: Treasure

Source Pathfinder RPG Bestiary pg. 293
A creature should have an amount of treasure appropriate to its CR. See Table 1–7 for a list of treasure totals based on CR. For some creatures, their treasure consists of the loot from their recent meals strewn across their lairs, while for others it consists of a greed-fueled hoard or even gear it uses in combat. Make sure to account for any weapons or armor that the creature is using, as determined by step 7.

Table 1-7: XP and GP Values by CR

CRXPSlow GPMedium GPFast GP
1/850 XP20 gp35 gp50 gp
1/665 XP30 gp45 gp65 gp
1/4100 XP40 gp65 gp100 gp
1/3135 XP55 gp85 gp135 gp
1/2200 XP85 gp130 gp200 gp
1400 XP170 gp260 gp400 gp
2600 XP350 gp550 gp800 gp
3800 XP550 gp800 gp1,200 gp
41,200 XP750 gp1,150 gp1,700 gp
51,600 XP1,000 gp1,550 gp2,300 gp
62,400 XP1,350 gp2,000 gp3,000 gp
73,200 XP1,750 gp2,600 gp3,900 gp
84,800 XP2,200 gp3,350 gp5,000 gp
96,400 XP2,850 gp4,250 gp6,400 gp
109,600 XP3,650 gp5,450 gp8,200 gp
1112,800 XP4,650 gp7,000 gp10,500 gp
1219,200 XP6,000 gp9,000 gp13,500 gp
1325,600 XP7,750 gp11,600 gp17,500 gp
1438,400 XP10,000 gp15,000 gp22,000 gp
1551,200 XP13,000 gp19,500 gp29,000 gp
1676,800 XP16,500 gp25,000 gp38,000 gp
17102,400 XP22,000 gp32,000 gp48,000 gp
18153,600 XP28,000 gp14,000 gp62,000 gp
19204,800 XP35,000 gp53,000 gp79,000 gp
20307,200 XP44,000 gp67,000 gp100,000 gp
21409,600 XP56,000 gp84,000 gp126,000 gp
22615,000 XP70,000 gp105,000 gp158,000 gp
23820,000 XP88,000 gp132,000 gp198,000 gp
241,230,000 XP110,000 gp165,000 gp248,000 gp
251,640,000 XP138,000 gp208,000 gp312,000 gp

Step 10: Details

Source Pathfinder RPG Bestiary pg. 293
Now that you have all of the creature’s statistics sorted out, it’s time to fill in all the details—such as name, alignment, space, reach, environment, and ecology—as you see fit.

Monster Advancement

Source Pathfinder RPG Bestiary pg. 294
The following rules allow you to adjust monsters, increasing (or even decreasing) their statistics and abilities while still creating a balanced and fun encounter.

Templates

Source Pathfinder RPG Bestiary pg. 294
A template is a set of rules that you apply to a monster to transform it into a different monster. All templates give precise directions on how to change a monster’s statistics to transform it into the new monster.

Acquired Templates: Some templates, like the lich, are the results of a creature’s choice and desire to transform. Others, like the ghost template, are the result of an external force acting upon a creature (for example, when a tormented person dies and becomes a ghost). Yet in both cases, the template changed a creature well after its birth or creation—these types are called “acquired templates,” and can be added to a creature at any time during its existance.

Inherited Templates: Some templates, such as the half-dragon and half-fiend templates, are part of a creature from the beginning of its existence. Creatures are born or created with these templates already in place, and have never known life without them. These types of templates are called “inherited templates.”

Adding Racial Hit Dice

Source Pathfinder RPG Bestiary pg. 295
Adding racial Hit Dice to a monster is a similar process to building a monster from scratch. As additional Hit Dice are added, other abilities increase in power as well. Additional Hit Dice usually results in better attack bonuses, saves, hit points, and skills, as well as more feats. It can also include additional spellcasting capability and other powers.

Step 1: Plan the Monster

Source Pathfinder RPG Bestiary pg. 295
When advancing a monster by adding racial HD, you should start by deciding what you want the monster to become. In most cases, this means merely a tougher, stronger version of an existing monster. Note the desired CR of the new monster. This is also the point at which you should decide whether the creature is going to increase in size. As a general rule, creatures whose Hit Dice increase by 50% or more should also increase in size, but GMs should feel free to ignore this rule if warranted by the individual creature or situation.

Step 2: Add Hit Dice

Source Pathfinder RPG Bestiary pg. 295
Next, determine how many Hit Points the base monster receives per Hit Die (see Table 1–5 for average results based on the die type). Using Table 2–1, add up all of the values in the Hit Point Change column for each increase using the Higher CR column. For example, if the base monster was CR 3 and the new monster is set to be CR 5, the total would be 25 hit points. Next, add additional Hit Dice to the monster to increase its hit points by the desired amount. Note that if the creature increases in size, its Constitution may also increase, as noted on Table 2–2, granting it additional hit points that might offset the need for additional Hit Dice (this also applies to any other Constitution increases).

These values are not absolute. Some monsters have fewer hit points than normal for a creature of their CR and rely on a higher AC or other defenses. Some creatures are primarily spellcasters and typically have fewer Hit Dice. When advancing your monster in this way, be sure to take these factors into account and adjust your monster accordingly.

Table 2-1: Monster Advancement

Higher CRLower CRHit Point ChangeAC ChangeAttack Bonus ChangeDamage Change
1Less than 15112-3
215212-3
321011-22-3
4310222-3
541511-23-4
651511-23-5
761511-24-5
871511-24-5
981521-24-5
10915113-5
111015114-5
12111521-24-5
131220114-5
141320113-5
151420114-5
16152011-28-10
171630117-10
181730118-10
191830117-10
201940218-10
21+20+40218-10


Table 2-2: Size Changes

Old Size*New SizeStrDexConNatural Armor
FineDiminutiveSame-2SameSame
DiminutiveTiny+2-2SameSame
TinySmall+4-2SameSame
SmallMedium+4-2+2Same
MediumLarge+8-2+4+2
LargeHuge+8-2+4+3
HugeGargantuan+8Same+4+4
GargantuanColossal+8Same+4+5
* Repeat the adjustment if the creature moves up more than one size.

Step 3: Ability Scores

Source Pathfinder RPG Bestiary pg. 296
Once you have determined the number of additional Hit Dice possessed by the creature, use this number to modify its other statistics. Start with ability scores. For every 4 additional Hit Dice gained by the monster, add 1 to one of its ability scores. In addition, make any modifications to its ability scores based on an increase in size, as noted on Table 2–2.

Step 4: Skills and Feats

Source Pathfinder RPG Bestiary pg. 296
When adding skills, check to see if the creature’s Int modifier changed. If it is unchanged, simply multiply the total number of ranks per Hit Dice gained by a monster of its type times the total number of added Hit Dice and add that number of ranks to its existing skills. If its Intelligence modifier has increased, perform the same calculation as if it had not increased and then multiply the change in its Intelligence modifier times its new total number of Hit Dice and add that number of additional ranks as well (adding new skills as needed to spend all of the ranks). If the creature changed size, make sure to adjust its Fly skill and Stealth skill bonuses (if any) as noted on Table 2–3.

Next, give the creature additional feats. Creatures gain one feat at 1 Hit Die and one additional feat for every 2 Hit Dice above 1. Most additional feats should be focused on increasing the creature’s combat abilities, but metamagic feats and skill feats are also possible choices depending on the creature’s role.

Table 2-3: Size Bonuses and Penalties

SizeAC/AttackCMB/CMDFly SkillStealth Skill
Fine+8-8+8+16
Diminutive+4-4+6+12
Tiny+2-2+4+8
Small+1-1+2+4
Medium+0+0+0+0
Large-1+1-2-4
Huge-2+2-4-8
Gargantuan-4+4-6-12
Colossal-8+6-8-16

Step 5: Statistics

Source Pathfinder RPG Bestiary pg. 296
Next, adjust the creature’s derived statistics, such as its initiative, AC, saving throws, melee and ranged attack bonuses, BAB, CMB, and CMD. Adjust any special attacks or qualities that are based on the creature’s size, Hit Dice, or ability scores. If the creature changed in size, be sure to adjust its AC, attack, CMB, and CMD accordingly (as noted on Table 2–3). Table 2–1 also tracks the average change to the creature’s AC, attack rolls, and damage rolls. Add up these values for each step of change between the creature’s original and new CR. If the creature changed size, make sure to make changes to its natural armor bonus, as noted on Table 2–2. If the creature does not meet these averages, you should consider adjusting its ability scores or Hit Dice to get it closer to the target.

Step 6: Comparison

Source Pathfinder RPG Bestiary pg. 296
Finally, compare the new monster’s statistics to those presented on Table 1–1 for a creature of its adjusted CR. Note that if the original creature deviated from these values, the new one should do so in a similar fashion. For example, if the original creature had higher than normal hit points but a lower than normal CR, the creature should maintain that balance at a higher CR (even though its hit points and AC both increased).

Adding Class Levels

Source Pathfinder RPG Bestiary pg. 296
Of all the methods of advancing a monster, adding class levels requires the most adjudication and careful comparison. Some classes truly add to the power and abilities of some monster types, while others do not. For example, adding levels of barbarian to a hill giant can be a great addition, whereas adding levels of sorcerer is less useful. When adding class levels to a creature, take the following three steps.

Step 1: Determine Creature’s Role

Source Pathfinder RPG Bestiary pg. 297
When adding class levels to a creature, the first step is to determine what role the base creature fulfills. There are three basic roles into which a creature might fall. A creature can fall into more than one role if its abilities are diverse.

Combat: This creature is designed to be good at melee or ranged combat with a weapon or its natural weapons. In either case, these monsters have a number of feats and abilities to enhance their combat prowess (or are good simply by nature of their Hit Dice and ability scores). If a creature does not possess many spells, special abilities, or skills, it is a combat monster.

Most animals, constructs, dragons, humanoids, magical beasts, monstrous humanoids, plants, and vermin fall into this role, as do some creatures of all the other types.

Spell: Spell creatures possess a large number of spells that allow them to attack or harass their enemies. These creatures usually have lower hit points and relatively weak attacks as compared to the averages for creatures of their CR. Note that creatures that only possess spell-like abilities do not fall into this role, and are usually considered combat or special.

Most dragons and outsiders fall into this role, but any creature that has a list of spells prepared or spells known likely falls under this heading as well.

Skill: Creatures of this type rely on skills (usually Stealth) to ambush or take down their prey. This also includes creatures who take advantage of the environment or spells, such as fog or invisibility.

Some aberrations, fey, magical beasts, monstrous humanoids, and outsiders fall into this role.

Special: Creatures that do not fall into any of the other categories usually rely on special abilities and powers to attack their foes. They might be tough or dangerous in physical combat, but the threat is greatly increased by their special abilities. A list of monster roles for determining key classes appears in each Beastiary.

Step 2: Add Class Levels

Source Pathfinder RPG Bestiary pg. 297
Once you have determined the creature’s role, it’s time to add class levels. The first step of this process is to modify the creature’s ability scores. Creatures with class levels receive +4, +4, +2, +2, +0, and –2 adjustments to their ability scores, assigned in a manner that enhances their class abilities. Creatures with NPC class levels do not receive adjustments to their ability scores.

Next, add the class levels to the monster, making all of the necessary additions to its HD, hit points, BAB, CMB, CMD, feats, skills, spells, and class features. If the creature possesses class features (such as spellcasting or sneak attack) for the class that is being added, these abilities stack. This functions just like adding class levels to a character without racial Hit Dice.

A monster with class levels always possesses treasure equal to an NPC of a level equal to the monster’s final CR (as calculated in Step 3, below). To determine the value of this gear, use the value listed for a heroic NPC of that level. Once a total GP value is determined, follow the rules for outfitting an NPC as outlined in that chapter. Gear should help a monster with class levels remain challenging and retain statistics close to those presented on Table 1-1: Monster Statistics by CR.

Step 3: Determine CR

Source Pathfinder RPG Bestiary pg. 297
Determining the final CR for a creature with class levels requires careful consideration. While adding a class level to a monster that stacks with its existing abilities and role generally adds 1 to its CR for each level taken, adding classes that do not stack is more complicated.

Table 2–4 gives general guidelines regarding which core classes add directly to a monster’s abilities based on its role. Classes that are marked “key” generally add 1 to a creature’s CR for each level added. Classes marked with a “—” increase a creature’s CR by 1 for every 2 class levels added until the number of levels added are equal to (or exceed) the creature’s original CR, at which point they are treated as “key” levels (adding 1 to the creature’s CR for each level added). Creatures that fall into multiple roles treat a class as key if either of its roles treat the class as key. Note that levels in NPC classes are never considered key.

Table 2-4: Monsters with Class Levels

Monster RoleBarbarian, Fighter, RangerCleric, Druid, Sorcerer, WizardBard, RogueMonk, Paladin
CombatKey
SpellKey*
SkillKeyKey
Special
* This class is only key if its spellcasting levels stack with those possessed by the creature.

Monsters as PCs

Source Pathfinder RPG Bestiary pg. 313
Using one of the monsters presented in this book as a character can be very rewarding, but weighing such a character against others is challenging. Monsters are not designed with the rules for players in mind, and as such can be very unbalancing if not handled carefully.

There are a number of monsters in this book that do not possess racial Hit Dice. Such creatures are the best options for player characters, but a few of them are so powerful that they count as having 1 class level, even without a racial Hit Die. Such characters should only be allowed in a group that is 2nd-level or higher.

For monsters with racial Hit Dice, the best way to allow monster PCs is to pick a CR and allow all of the players to make characters using monsters of that CR. Treat the monster’s CR as its total class levels and allow the characters to multiclass into the core classes. Do not advance such monsters by adding Hit Dice. Monster PCs should only advance through classes.

If you are including a single monster character in a group of standard characters, make sure the group is of a level that is at least as high as the monster’s CR. Treat the monster’s CR as class levels when determining the monster PC’s overall levels. For example, in a group of 6th-level characters, a minotaur (CR 4) would possess 2 levels of a core class, such as barbarian.

Note that in a mixed group, the value of racial Hit Dice and abilities diminish as a character gains levels. It is recommended that for every 3 levels gained by the group, the monster character should gain an extra level, received halfway between the 2nd and 3rd levels. Repeat this process a number of times equal to half the monster’s CR, rounded down. Using the minotaur example, when the group is at a point between 6th and 7th level, the minotaur gains a level, and then again at 7th, making him a minotaur barbarian 4. This process repeats at 10th level, making him a minotaur barbarian 8 when the group reaches 10th level. From that point onward, he gains levels normally.

GMs should carefully consider any monster PCs in their groups. Some creatures are simply not suitable for play as PCs, due to their powers or role in the game. As monster characters progress, GMs should closely monitor whether such characters are disruptive or abusive to the rules and modify them as needed to improve play.