[3.5] Swapping arcane spell for divine?

[Petrocorus]

Is there a dual-casting PrC that allows to convert an arcane spell slot into a divine or vice-versa?

[Elric VIII]

Geomancer allows you to cast arcane spells as divine or divine spells as arcane and choose which casting stat dictates their DC. It requires both arcane and divine spells to enter. I'll let someone else link to the various early entry tricks. This is in CDiv I believe and only advances one side at a time.


There are a few feats that would let you do this on any theurge:

Southern Magician allows you to cast divine spells as arcane or arcane spells as divine once per 2 caster levels. This is from Races of Faerun and is a regional feat. It also gives enemies a penalty on counterspell/dispels against affected spells if they do not have this feat.

Alternative Source Spell is a +0 metamagic that allows you to cast arcane spells as divine or divine spells as arcane at the cost of one caster level for the affected spells. This is from Dragon 325.

Southern Magician seems to let you choose to make the conversion on the fly, whereas Alternative Source spell requires you to prepare it that way.