Theurgy

You can augment the power of your divine spells with arcane energy and augment your arcane spells with divine energy.

When casting a divine spell, you may sacrifice an arcane spell slot or arcane prepared spell of that spell's level or higher as a swift action. The caster level for that divine spell increases by +1.

When casting an arcane spell, you may sacrifice a divine spell slot or prepared divine spell of the sam