The Moonlight Stone (月の石 Tsuki no Ishi, lit. "Moon Stone") is an object which was made by the evil mamodo, Zofis. It was used to manipulate the hearts of the many humans and Ancient Mamodo who fought in his "army". That object produces a light which can replicate that of the moon and initially was used to free all the Ancient Mamodo from their Stone Tablets. The Moonlight Stone can also heal injuries and restore heart strength of humans, who have their minds and heart controlled so that they do anything that their mamodo partner wants, like cast a spell, without the mamodo saying anything. However, not all the humans who fought with the Ancient Mamodo had their minds controlled, like Gensou, Dalia Anjé and Robert Vile.
So Giaku destroying the moon stone
The Moonlight Stone was protected by Demolt, a massive Mamodo who is not very smart. Because of the stone, a team of six mamodo teams: Zatch Bell and Kiyo Takamine, Tia and Megumi Oumi, Kanchomé and Parco Folgore, Ponygon and Kafka Sunbeam, Wonrei and Li-en and Kido and Dr. Riddles, invade the Devolo Ruins to destroy the Moonlight Stone. Eventually, it was destroyed by Penny and Uri, with help from Byonko and Alvin, using her strongest spell So Giaku. Vile, the bookkeeper of Demolt was a greedy man who wanted Moonlight Stone for his own use. Because using it he can manipulate humans but it was a lie.
