Questions About Advanced Monsters

A few questions about advanced monsters:

1) Saving Throw Changes: How do saving throws increase after a template (like becoming an outsider) or other event changes them? If a creature had a poor saving throw and 11 hit dice (base save +3) which of the following would be true if it gain a hit die as a good saving throw:

a) It increases to a +4 because the change on a good saving throw is only a +1 from level 11 to 12…
b) It increases to a +5 because the first level of a good save increase is a +2…

2) DCs for SU and SP powers: Both of these are listed as special attacks. In general the DC is half the Hit Dice plus governing attributes. I swear I read somewhere that character classes don’t count in this DC calculation though. Savage Species seems to indicate that Monstrous Prestige Classes seem to count (based on the examples). So, which of the following count for this DC calculation:
a) Base Hit Dice (of course they do)
b) Advanced Monster Hit Dice from Type
c) Character Class and NPC Class levels
d) Prestige Class levels
e) Monstrous Prestige Class levels

3) Spell-Like Powers: These have always thrown me off. It always gives an equivalent caster level, but the DCs are always calculated by Special Attack (1/2 Hit Dice + Attribute) right? Is the caster level simply for duration and dispelling purposes?

4) Innate Spell Casting: Some special creatures have innate spell casting powers such as the Nymph whom gains spells and casts as a 7th level druid (though she has only 6 hit dice). Do these powers increase when advancing the Hit Dice of the creature (such as pumping the nymph from a HD 6 to a HD 12)? If the nymph took a character class (such as druid) would these spell casting levels stack? If the nymph takes a special class that lets her “increase existing spell casting level by +1” can she increase her effective druid caster level?

1) Most of the time, when a creature changes type due to a template, it retains the features of the base creature except those that are noted to be changed (Features are Hit Dice size, Base Attack progression, Save progression, and number of Skill Points). In your example, I believe the correct answer would be a), but not because of your reasoning, but because a bad save for a 12 HD creature is +4. If it changed to a good save, it would be +8.

2) From the SRD/Introduction in the MM.

Special Attacks and Special Qualities
Many creatures have unusual abilities. A monster entry breaks these abilities into special attacks and special qualities. The latter category includes defenses, vulnerabilities, and other special abilities that are not modes of attack. A special ability is either extraordinary (Ex), spell-like (Sp), or supernatural (Su). Additional information (when needed) is provided in the creature’s descriptive text.
When a special ability allows a saving throw, the kind of save and the save DC is noted in the descriptive text. Most saving throws against special abilities have DCs calculated as follows: 10 + 1/2 the attacker’s racial Hit Dice + the relevant ability modifier.

Click to expand...

So, usually the answer is a) and b). In some cases, all class levels are added, but those are typically undead templates.

3) No, the DC for spell-like abilities is calculated as 10 + the level of the spell the ability resembles or duplicates + the creature’s Cha modifier.

4) By the rules, simply advancing by HD does not increase the spellcasting.
Taking levels as a druid would increase the spellcasting ability, but note that it would have only the class features of a druid 6 levels lower.
Taking levels in a PrC that can increase spellcasting levels also increases the creatures spellcasting levels.

Thanks for the quick and excellent responses Ashardalon. I have two more however.

1) I knew that you don’t re-do the abilities for changing type, but… Say a creature acquired a template such as half-fiend and was originally a monstrous humanoid (I know you can’t normally acquire the half-fiend template but bear with me). Its type would change to monstrous humanoid. If I advance the monster, can I advance it as an outsider? The creature no longer has the monstrous humanoid type, so I would assume that I would have to advance it as an outsider. Is this logic wrong, or do I have to advance a creature by its original type only? Does that mean undead advance as their original type. If they do advance as their new type, then my question about saving throws becomes valid, as their saves have now become better or worse (such as a giant to undead, who would then have a good will save, right?)

2) Do Monstrous Prestige classes count as Racial Hit Dice for DC calculations? As I said before, I think Savage Species indicates they do, but I can’t find text (but their example monsters seem to indicate that this is true).

Also, is there a SRD or text passage about the spell-like powers. Perhaps I am just fatigued but I can’t seem to find it.

(Let's try this again - lost an earlier reply due to a misclick)

1) Usually, when a creature changes types, it gains the Augmented subtype, which means that it retains most of the features of the former type. That means that advancing the monster still follows the rules of the old type. There are sometimes templates that change one or more of the features, however. In case of the half-fiend, it changes the number of skill points at each racial Hit Die. Some undead templates change both racial and class hit dice to d12.
When advancing such a creature, you would use the original feature where they were not overwritten by the template, and the new features that the template has granted.
The zombie and skeleton templates, on the other hand, fully change the creature over to the new type, and does not gain the Augmented subtype. If you were to advance a zombie or skeleton, you would use the standard Undead features.

2) By the rules as written, I don't think they count. Monstrous Prestige Class levels are still class levels and not racial hit dice. SavSpe is somewhat caught between 3E and R3E, though, and sometimes includes rules that were part of the revised rules back then, but changed again, such as the fire and cold subtypes.
It is interesting to note, though, that templates that scale with hit dice usually do count class levels - one exception would be the Feral template from SavSpe, whose Special Attacks paragraph says to only use racial hit dice.

For the spell-like abilities, the SRD file you'll want to check is Types, Subtypes and Abilities, the Special Abilities entry.