How about one more Pathfinder feat, this time to deal with undead only….
The candle that burns the brightest burns the quickest.
Prerequisite: Ability to cast spells with the light descriptor or the ability to use spell like abilities with the light descriptor that have an effective level such as an alchemist
Benefit: As a standard action you cay lose a prepared spell you have and select a light source within 60 feet of you. That light source instantly emits a burst of blinding light that is only harmful to undead creatures as per the Sunburst spell but it only effects undead creatures and uses the spell level that was lost as your level. As an example, if a wizard lost a 3-rd level spell, this feat would cause 3d6 damage to undead in the area. The light source is is extinguished after the spell takes place and does not extinguish any area of magical darkness in its radius but will effect undead in that darkness if the darkness if of an equal or lower spell level. Any additional effects from being exposed to sunlight still effect undead in the radius. If the light source is held by a creature that does not want the light lost, the creature makes a will save equal to 10+spell casting attribute+level of the spell lost