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Bestiary

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 CR	Lower CR	Hit Point Change	AC Change	Attack Bonus Change	Damage Change
1	Less than 1	5	1	1	2-3
2	1	5	2	1	2-3
3	2	10	1	1-2	2-3
4	3	10	2	2	2-3
5	4	15	1	1-2	3-4
6	5	15	1	1-2	3-5
7	6	15	1	1-2	4-5
8	7	15	1	1-2	4-5
9	8	15	2	1-2	4-5
10	9	15	1	1	3-5
11	10	15	1	1	4-5
12	11	15	2	1-2	4-5
13	12	20	1	1	4-5
14	13	20	1	1	3-5
15	14	20	1	1	4-5
16	15	20	1	1-2	8-10
17	16	30	1	1	7-10
18	17	30	1	1	8-10
19	18	30	1	1	7-10
20	19	40	2	1	8-10
21+	20+	40	2	1	8-10

Table 2-2: Size Changes

Old Size*	New Size	Str	Dex	Con	Natural Armor
Fine	Diminutive	Same	-2	Same	Same
Diminutive	Tiny	+2	-2	Same	Same
Tiny	Small	+4	-2	Same	Same
Small	Medium	+4	-2	+2	Same
Medium	Large	+8	-2	+4	+2
Large	Huge	+8	-2	+4	+3
Huge	Gargantuan	+8	Same	+4	+4
Gargantuan	Colossal	+8	Same	+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

Size	AC/Attack	CMB/CMD	Fly Skill	Stealth 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 Role	Barbarian, Fighter, Ranger	Cleric, Druid, Sorcerer, Wizard	Bard, Rogue	Monk, Paladin
Combat	Key	—	—	—
Spell	—	Key*	—	—
Skill	Key	—	Key	—
Special	—	—	—	—

* This class is only key if its spellcasting levels stack with those possessed by the creature.

Archives of Nethys

Rules Index | GM Screen

Table 2-1: Monster Advancement

Table 2-2: Size Changes

Table 2-3: Size Bonuses and Penalties

Table 2-4: Monsters with Class Levels