Ultimate Magus question

[With a box]

The requirements for Ultimate Magus (CM 77, a dual-class caster PrC designed for sorc/wizard) are "able to spontaneously cast 1st level arcane spells and able to prepare and cast 2nd level arcane spells."

Could a 3rd level wizard with Spontaneous Divination (able to spontaneously cast all divination spells) and no class levels in another class take this PrC? (well we can delay a level or two for skill requirements) What would happen? Would wizard casting increase twice every level and get 9th spell at 12th?

[Story]

First off, you have to be level 5 to take Spontaneous Divination.

Anyway, there's no definite RAW answer, but I think most DMs would take the sane approach and say no. You will find people here who give you every one of those answers though.

On a side note, even if the same class qualifies on both sides, double progression doesn't necessarily follow. Gaining a single level in the class fulfills the text of gaining a level in the prepared class and gaining a level in the spontaneous class, so even if you allow qualification, the interpretation of double progression can still go either way.

[Biffoniacus_Furiou]

UM requires Spellcraft 8 ranks as well, so you have to be at least 5th level to qualify for it, plus a Wizard has to be 5th level to even be able to get Spontaneous Divination.

The Wizard class is identified as a prepared spellcasting class, just like Cleric and Druid are identified as prepared spellcasting classes. That these classes may gain the capability of spontaneously converting those prepared spells into a different spell does not make them spontaneous spellcasting classes. Thus you cannot use UM to double-up your Wizard spellcasting advancement, since it cannot be advanced with the "+1 level of existing spontaneous arcane casting class" of UM.

While similar, being able to spontaneously convert a prepared spell into a different spell and being able to spontaneously cast spells using open spell slots are not the same thing. There are a few abilities which will allow a prepared caster to actually use an open, normally prepared spell slot to spontaneously cast a spell, but even these abilities don't count the Wizard class as a spontaneous spellcasting class. You may have a spontaneous spellcasting character, but a given character's capabilities do not modify the classes at large. Otherwise you could point to some other Wizard who can spontaneously cast spells using his Wizard spell slots, and use that to conclude that Wizard is a spontaneous spellcasting class without having to put any effort into it yourself.

[DevilsAttorney]

As the poster above me said, you can indeed qualify for UM with Spontaneous Divination. You would however only be able to advance Wizard once every level, as it does not qualify as a spontaneous caster class (even with the feat). UM requires for you to be able to cast a spontaneous arcane spell but does not require you to HAVE an spontaneous arcane class. It does, however, require you to have one in order to benefit from the +1 to spontaneous caster class.

So in short, yes you can, but there is no reason. Any other (most...) arcane prestige class would be tons better in that case, since you couldn't use the UM's signature ability: "Augmented Casting (Su): Starting at 3rd level, you can choose to sacrifice a spell or spell slot from one of your classes to apply the effect of a metamagic feat that you know to a spell cast using another arcane class." Just one class means you can't satisfy the requirements to use Augmented Casting.

[Dalebert]

Probably the biggest exploit with UM is a feat that allows you to cast a 2nd level spell at 1st level. It's very limited but it's apparently enough to qualify for the one of the prereqs such that you only have to be 1st level in one of the two classes. I forget the name of the feat at the moment. You still have to be 5th in character levels due to the spellcraft reqt, of course, but it means only dipping one level of your highest caster class as opposed to three.

[DevilsAttorney]

Probably the biggest exploit with UM is a feat that allows you to cast a 2nd level spell at 1st level. It's very limited but it's apparently enough to qualify for the one of the prereqs such that you only have to be 1st level in one of the two classes. I forget the name of the feat at the moment. You still have to be 5th in character levels due to the spellcraft reqt, of course, but it means only dipping one level of your highest caster class as opposed to three.

Precocious apprentice... But it's not really worth it, since it is much better to level your prepared class instead of your spontaneous, giving you both requirements (Spotaneous 1, prepared 4 for example).