MONSTERS AND CLASS LEVELS
The creature's Hit
Dice equal the number of
class levels it has plus its racial Hit
Dice. A creature's "
monster class" is always a
favored class, and the creature never takes XP penalties for having it. Additional Hit
Dice gained from taking levels in a character class never affect a creature's size.
Humanoids and Class Levels: Creatures with 1 or less HD replace their
monster levels with their character levels. The
monster loses the
attack bonus,
saving throw bonuses, skills, and feats granted by its 1
monster HD and gains the
attack bonus, save bonuses, skills, feats, and other class abilities of a 1st-level character of the appropriate class.
Level Adjustment and Effective Character Level: To determine the effective character level (ECL) of a
monster character, add its level adjustment to its racial Hit
Dice and character
class levels. The
monster is considered to have experience points equal to the minimum needed to be a character of its ECL.
If you choose to equip a monster with gear, use its ECL as its character level for purposes of determining how much equipment it can purchase. Generally, only
monsters with an Advancement entry of "By character class" receive NPC gear; other creatures adding character levels should be treated as
monsters of the appropriate CR and assigned treasure, not equipment.
Feat Acquisition and Ability Score Increases: A
monster's total Hit
Dice, not its ECL, govern its acquisition of feats and ability score increases.