You have reached the pinnacle of magical power, and your ability to synthesize spells from two sources is even more powerful than before.

Prerequisite(s): Spellcraft 17 ranks, 10th-level Mystic Theurge

Benefit: When you use your spell synthesis ability, any target affected by both of the spells takes an additional -2 penalty on saves made against the spells (for a total of -4) and you receive an additional +2 bonus on caster level checks made to overcome spell resistance with these two spells (for a total of +4). If you cast at least one arcane spell and one divine spell within the last two rounds, these bonuses increase by 2, to -6 and +6.