Idolmaster: Xenoglossia centers around mecha and re-imagines the ten prospective idols from The Idolmaster as fighter pilots of those robots, with eight of them also posing as students. The large robots are called Immortal Defender of Legatee (IDOL) and their pilots are called Idolmasters. IDOL pilots have to be girls, and they have to be chosen by the IDOL itself. The Moon was destroyed 107 years prior to the beginning of the story in an event called Lost Artemis. This event caused numerous fragments to fall onto the Earth, which killed about one quarter of the Earth's total population. The remaining fragments of the Moon which orbit around the Earth are called Kompeito or Confeito. Once a fragment falls onto Earth, it is called a Drop.