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A character may add new classes as he or she progresses in level, thus becoming a multiclass character. The class abilities from a character’s different classes combine to determine a multiclass character’s overall abilities. Multiclassing improves a character’s versatility at the expense of focus.
Class and Level Features
As a general rule, the abilities of a multiclass character are the sum of the abilities of each of the character’s classes.
“Class level” is a character’s level in a particular class. For a character whose levels are all in the same class, character level and class level are the same.
Base Attack Bonus
Add the base attack bonuses acquired for each class to get the character’s base attack bonus. A resulting value of +6 or higher provides the character with multiple attacks.
Add the base save bonuses for each class together.
If a skill is a class skill for any of a multiclass character’s classes, then character level determines a skill’s maximum rank. (The maximum rank for a class skill is 3 + character level.)
If a skill is not a class skill for any of a multiclass character’s classes, the maximum rank for that skill is one-half the maximum for a class skill.
A multiclass character gets all the class features of all his or her classes but must also suffer the consequences of the special restrictions of all his or her classes. (Exception: A character who acquires the barbarian class does not become illiterate.)
In the special case of turning undead, both clerics and experienced paladins have the same ability. If the character’s paladin level is 4th or higher, her effective turning level is her cleric level plus her paladin level minus 3.
In the special case of uncanny dodge, both experienced barbarians and experienced rogues have the same ability. When a barbarian/rogue would gain uncanny dodge a second time (for her second class), she instead gains improved uncanny dodge, if she does not already have it. Her barbarian and rogue levels stack to determine the rogue level an attacker needs to flank her.
In the special case of obtaining a familiar, both wizards and sorcerers have the same ability. A sorcerer/wizard stacks his sorcerer and wizard levels to determine the familiar’s natural armor, Intelligence score, and special abilities.
A multiclass character gains feats based on character levels, regardless of individual class level
A multiclass character gains ability score increases based on character level, regardless of individual class level.
The character gains spells from all of his or her spellcasting classes and keeps a separate spell list for each class. If a spell’s effect is based on the class level of the caster, the player must keep track of which class’s spell list the character is casting the spell from.
If you have levels in more than one psionic class, you combine your power points from each class to make up your reserve. You can use these power points to manifest powers from any psionic class you have.
One of the standard eleven classes.
A character’s favored class doesn’t count against him or her when determining experience point penalties for multiclassing.
Prestige classes offer a new form of multiclassing. Unlike the basic classes, characters must meet Requirements before they can take their first level of a prestige class. The rules for level advancement apply to this system, meaning the first step of advancement is always choosing a class. If a character does not meet the Requirements for a prestige class before that first step, that character cannot take the first level of that prestige class. Taking a prestige class does not incur the experience point penalties normally associated with multiclassing.
Epic Prestige Classes
These are classes that characters cannot pursue until they have already become epic characters in some other fashion. Characters add levels of epic prestige classes using the same rules as when multiclassing into a new character class at epic levels. As with other epic classes, a character can take as many levels in an epic prestige class as he or she desires.
Monsters and Class Levels
See Improving Creatures.