multiclassing question

[parinho7]

let's say i am a sorcerer(4) and then take a bunch prestige classes that increase my caster level until level 18. then i take a fifth level in sorcerer but i want to take the domain access acf. do i take it at character level 18 or at character level 5? i think at level 18 but i don't learn a bonus 1st and 2nd level spell at this level. how does it work? what do i replace to take that acf?

 

[Dandu]

You can probably take the ACF at sorcerer level 5 or the equivalent thereof if you prestige class before that, since it replaces spells.

Might not hold up to a strict RAW reading, but the RAW reading becomes problematic if you delay Sorcerer 5 until later.

 

[Herzog]

I think, strictly speaking, you cannot take the ACF.
Although your sorcerer lvl is 5, your spellcasting has progressed to lvl 18, and since you do not normally get the substituted spells at that level, you cannot replace them.

I agree with Dandu that you can probably use the substitution at the appropriate PrC lvl (the one where your increased sorcerer progression would be at lvl 5) since the substitution replaces something related to the increase. If the PrC only increases your caster level (and has no other spellcasting increase) you should wait until you actually increase your spells per day/spells known to the equivalent of a 5th lvl sorcerer.

Slightly different example: a Kobold sorcerer using the Races of the Dragon Web-enhancement to get an extra lvl of sorcerer, would count as a 4th lvl sorcerer (including spellcasting) at lvl 3, and would therefore be required to take the substitution lvl at level 4 (the level where he gets his new spells known that are replaced by the substitution level)

If you really need to replace them at lvl 18, you could consider it a slightly modified version of the Retraining rules (from PH2).