Long ago, there was a great massacre in the kingdom, which arose because of the fight between the groups of wizards. The details were unknown, but the wizards of all of the kingdom started to become ill. The illness was not something related to their body, but their mind.
The wizards from all over the land became violent and started to kill each other. All of the wizards of the time died as they killed each other. When their kids grow up and survive the illness, they pull their magic out from themselves seal those magic inside the stone and hide those stones somewhere in this world. The first monarchy to find such a stone was the kingdom of Xandria
After that, many stones became visible all over the world too. Because of that, it created a group of all nations who sighed the treaty, agreeing to tell the story of the discovery of magic stone within all nations if they found it within their nation.