Advanced Monster Caster Level

[Marimmar]

When advancing monsters by adding Hit Dice, what happens to the effective caster level of their spells and spell-like abilities? Do they increase their caster level by the same amount as the increase in Hit Dice or do they stay the same?

~Marimmar

 

[Patryn of Elvenshae]

The standard save DC calculation is 10 + 1/2 Hit Dice + Ability Mod.

EDIT: For a spell or spell-like ability, however, it's based on the spell level. So, there wouldn't be any change. I missed your qualifiers on my first pass - mi excusa.

For an aboleth, for instance:

Psionics (Sp): At will—hypnotic pattern (DC 15), illusory wall (DC 17), mirage arcana (DC 18), persistent image (DC 18), programmed image (DC 19), project image (DC 20), veil (DC 19). Effective caster level 16th. The save DCs are Charisma-based.

Note that the aboleth has a normal Charisma score of 17 (+3).

The spell-like ability save DCs are thus:

1. Hypnotic pattern (DC 15): 10 + 2 + 3
2. Illusory wall (DC 17): 10 + 4 + 3
3. Mirage arcana (DC 18): 10 + 5 + 3
4. Persistent image (DC 18): 10 + 5 + 3
5. Programmed image (DC 19): 10 + 6 + 3
6. Project image (DC 20): 10 + 7 + 3
7. Veil (DC 19): 10 + 6 + 3

So, they follow the same progression with Hit Dice that normal spells do - none.

 

[Marimmar]

It's not the save I'm asking about, it's the effective caster level.

e.g. I advance a Hezrou from 11 HD to 20 HD, does its effective caster level go from 13th to 22nd?

~Marimmar

 

[Patryn of Elvenshae]

It's not the save I'm asking about, it's the effective caster level.

e.g. I advance a Hezrou from 11 HD to 20 HD, does its effective caster level go from 13th to 22nd?

~Marimmar

Oh. Man, I'm way off today. I blame the snow!

The effective caster level, generally, doesn't change - unless the ability says otherwise. Dragons, for instance, increase their caster level at certain age ranges.

Couatls don't.

 

[Shin Okada]

Spells

Basically, spellcasting abilities are never improved when you advance monsters by HD. If you want to give them higher spell-casting ability, you must let them advance by adding appropriate class levels. For example, if you add 18 HD to a Spirit Naga, it is now a 27 HD huge monster. But it still casts spells as a 7th-level sorcerer. But if you add 10 levels of sorcerer class to a 9HD Spirit Naga, it now casts spells as a 17th level Sorcerer. It has 9 levels in racial HD (d8) and 10 levels in Sorcerer (10d4 HD).

Spell-Like abilities

Again, basically, advancing in HD never give creature a higher caster level or something. Sometimes, especially in the case of template monsters, the descriptive text of spell-like abilities say "Caster level equals the creature's HD" or something. In this case, if the creature's HD increases, then the caster level increases, too. But otherwise, increase in HD does not raise CL.

 

[Diirk]

That's not what he's asking, though. Take for example the Nymph. It has 6 hit dice, and yet both its spell like abilities, and its actual spells have a caster level of 7. If we advanced a nymph to 12, would its caster level be 13? 14? 7? Would only its caster level for spells raise and not SLA ?

I think thats what he meant to ask

The nymph probably isn't the best example, but thats the one I thought of first. And yeah I'd prob just add +1 CL for every HD if its CL was higher than its HD.. if its CL was lower than its HD, then not sure, its probably easiest to look at these things on a case by case basis.

 

[drunkmoogle]

The MM section on Advancing a Monster doesn't state that this changes, and thus remains the same. Just as a Gnome's SLAs stay locked at CL1.

You could get a one-time boost of up to +4 with Practiced Spellcaster if you really want it.

 

[Shin Okada]

You could get a one-time boost of up to +4 with Practiced Spellcaster if you really want it.

Practived Spellcaster feat is only for spellcasting classes. It does not add CL for spell-like abilities.

 

[drunkmoogle]

D'oh. Nice catch. Working from memory.

 

[Patryn of Elvenshae]

That's not what he's asking, though. Take for example the Nymph. It has 6 hit dice, and yet both its spell like abilities, and its actual spells have a caster level of 7. If we advanced a nymph to 12, would its caster level be 13? 14? 7? Would only its caster level for spells raise and not SLA ?

It doesn't change. See above.