The Child of Light has given you their favor, allowing you to use but a small portion of their power.
At will, as an action, you can empower the radiances of a Holy Light that surrounds you into a blazing glow that sheds bright light in a 15ft radius and dim light out to 20ft. Creatures within 10 feet of you take 2d4 points of Radiant damage per round that remain within your light.
Additionally, the unholy shirk from your touch, and burn in your light. If you cast a spell that would normally restore hit points on an undead creature, it instead deals radiant damage to them, equal to the number you would have restored, so long as they are within range.
This feat has the potential to evolve if favor with the Child of Light increases.