Spellcraft results:
Dolfgand, the pyromancer on the island was obviously using illusion spells or item to enhance the display, and was throwing in flashy evocation and conjuration spells.
Those streaks of light across the sky should have been out of range for him. These turned out to be the falling sky-rocks.
Religion: the image is a bit vague, but could be though to resemble the Symbols of an orc or death god.