Class Levels & Monster Caster Level

[Ogrork the Mighty]

If you add 4 class levels to a monster with 10 HD, does the monster's caster level for purposes of spell-like abilities stay at 10 or does it become 14?

In short, do class levels count for purposes of spell-like ability caster level?

 

[Shin Okada]

If you add 4 class levels to a monster with 10 HD, does the monster's caster level for purposes of spell-like abilities stay at 10 or does it become 14?

In short, do class levels count for purposes of spell-like ability caster level?

Usually not. But it depends on each monster's spell-like ability entry.

Some has fixed caster level which never improves (like Ogre Mage or most of the fiends).

Some has caster level equal to it's character level =HD (like drow or half-celestial/fiend). In this case, the total character level/HD, not ECL, is one's caster level for said spell-like ability. In this case, for example, Half-Fiend Ogre/10th-level Fighter has caster level of 14th for one's spell-like abilities from half-fiend template.

I guess there should be some monster which has caster level equal to one's racial HD only, but I cannot point one out immediately.

But anyway, usually, something with racial HDs and spell-like abilities as their racial ability does not add levels from classes to one's caster level for spell-like abilities.

 

[blargney the second]

I usually advance innate monster casting abilities if I add HD or appropriate class levels. Then just eyeball to make sure they're not suddenly out of CR whack.

 

[Corsair]

Some monsters who cast as a class will have that casting stack with additional levels of the class (rakshasa sorcerers, for instance).

 

[moritheil]

This is something I looked closely at for my Invasion campaign, in which most PCs are fiends. I ruled that innate SLA casting advances only with racial HD or something similar (i.e. bloodline levels.) Racial HD are actually very good for outsiders (particularly when they change size categories.) I don't feel that this is an unfair restriction at all, and it allows the player of an outsider to choose between focusing more on its heritage, or more on its acquired skills (i.e. classes.)

Of course, casting as a class should increase if you increase levels in that class.

Also note that most monsters have a limit on their racial HD progression; Sylphs can only take so many outsider HD before they need to progress as sorcerers (lower BAB, saves, and skills.)

 

[Shin Okada]

Some monsters who cast as a class will have that casting stack with additional levels of the class (rakshasa sorcerers, for instance).

Yeah. But Ogrork the Mighty is talking about spell-like abilities, not spells.