ADVANCED MONSTER CHALLENGE RATING
When
adding class levels to a creature with 1 or less HD, you advance the creature like a character. Otherwise, use the following guidelines.
When
adding class levels to a creature, you should give it typical ability scores appropriate for that class. Most creatures are built using the standard array of ability scores: 11, 11, 11, 10, 10, 10, adjusted by racial modifiers. If you give a creature a PC class use the
elite array of ability scores before racial adjustments: 15, 14, 13, 12, 10, 8. Creatures with NPC classes use the
nonelite array of 13, 12, 11, 10, 9, 8. T
Rogue and
ranger are associated classes for a creature that relies on stealth to
surprise its foes, or on skill use to give itself an advantage.
A spellcasting class is an associated class for a creature that already has
the ability to cast spells as a character of the class in question, since the
monster's levels in the spellcasting class stack with its innate spellcasting ability.
Nonassociated Class Levels
Levels in NPC classes are always treated as nonassociated.
When you improve a monster by
adding Hit Dice, use
Table: Improved Monster CR Increase to determine the effect on the creature's CR. Keep in mind that many
monsters that advance by
adding Hit Dice also increase in size. Do not stack this CR increase with any increase from
class levels. In general, once you've doubled a creature's CR, you should closely watch any additional increases in its abilities.
Adding Hit Dice to a creature improves several of its abilities, and radical increases might not follow this progression indefinitely. Compare the monster's improved
attack bonus,
saving throw bonuses, and any DCs of its
special abilities from the HD increase to typical characters of the appropriate level and adjust the CR accordingly.
|
Table: Improved Monster CR Increase
|
|
Creature's Original Type
|
CR Increase
|
| Aberration, construct, elemental, fey, giant, humanoid, ooze, plant, undead, vermin |
+1 per 4 HD added |
|
Animal, magical beast, monstrous humanoid |
+1 per 3 HD added |
| Dragon, outsider, nonassociated class levels |
+1 per 2 HD or 2 levels added |
| Directly associated class levels |
+1 per level added |
|
Other Modifiers:
|
|
| Size increased to Large or larger |
+1 to CR |
|
Monster's ability scores based on elite array* |
+1 to CR |
|
Monster possesses special attacks or qualities that significantly improve combat effectiveness |
+2 to CR |
|
Monster possesses special attacks or qualities that improve combat effectiveness in a minor way |
+1 to CR |
|
Template added |
+ template CR modifier |
| * Do not apply this increase if you advance a monster by class levels. (Monsters advanced by class levels are assumed to use the elite array.) |
Generally, increasing a
monster's
size increases its
combat effectiveness. Large creatures gain increased Strength, reach, and other benefits. Apply this modifier if you increase a creature beyond Medium and in conjunction with any other increases.
Be careful, though.
Monsters that benefit from a smaller size may actually lose effectiveness because of a
size increase.
Monsters that don't benefit from
size increases don't advance in that manner for this reason.
You can add any sort of spell-like, supernatural, or extraordinary ability to a creature. As with a
class level, you should determine how much, or how little, this ability adds to the creature's existing repertoire. A suite of abilities that work together should be treated as a single modifier for this purpose. If
the ability (or combination of abilities) significantly increases the
monster's
combat effectiveness, increase its CR by 2. Minor abilities increase the creature's CR by 1, and truly trivial abilities may not increase CR at all. If the
special abilities a
monster gains are not tied to a class or Hit Die increase, this CR increase stacks.
A significant
special attack is one that stands a good chance of incapacitating or crippling a character in one round. A significant special quality is one that seriously diminishes the
monster's vulnerability to common attacks. Do not add this factor twice if a
monster has both
special attacks and special qualities.
Make sure to "scale" your evaluation of these abilities by the
monster's current CR.