The Night Sun was a sentient star that put whole planets to sleep and fed harmlessly off of the dreams of their inhabitants.
Before it knew its own strength, it destroyed a planet made of sapphire and killed its population. A small number survived as blue lights stuck alone with the Night Sun, targeting the lonely among those that the Night Sun put to sleep and giving them waking nightmares.
The Night Sun came to Earth through the Rift and was allowed by God to feed off of humans' dreams. (AUDIO: Night Watch) She had allowed it to come through to restore balance after resurrecting St John Colchester. (AUDIO: Thoughts and Prayers) She sent Orr to watch over Cardiff, making sure that they came to no harm. They found the lights and reunited them. The Night Sun left at dawn. (AUDIO: Night Watch)