Manga spoilers: The Lunarians reveal that they are after Master Kongou all this time. The Lunarians are spirits that are unable to go to afterlife, and they need someone to pray for them in order to do so. Kongou is actually a robot created by humans for the purpose of making prayers, but he defied his programming and chose to take care of gems instead. All this time, the Lunarians attacked and kidnapped the gems because they believe they can use this method to make Kongou cooperate with and pray for them to help them go to afterlife. Phos, after learning about all this, decides to help the Lunarians get Kongou to pray for them so that they will no longer target the gems.
