Days of War

For four months out of the year, the rotation of Luxratha around its primary sun will cause the planet to drift closer to the path of the dwarf planet that the residents of the midnight expanse have nicknamed ‘War’ after their god of war. The proximity is not so much to throw off the planet’s own rotation, or pull War into a collision course, but it does become prominent enough to be noticed from ground level. Light reflects off War, creating the illusion of a second sun in the sky. This light makes the days almost unbearable without shelter, and nights bright, like a perpetual dawn.
  This light is not quite strong enough to banish the demon hordes from the surface of the planet, but it does make fighting them easier, since they lose their primary advantage of surprise against the races who are not typically capable of seeing in the dark.
  These weeks of bright light have become a time to push the demons back as much as possible, or train new recruits how to properly defend themselves and others against the demonic hordes.