Piedra Del Sol: The Sun Stone (太陽の石, Taiyō no Ishi?) is the Noble Phantasm of Quetzalcoatl. Normally, this Noble Phantasm is the Sun Stone that is engraved with the Aztec calendar. However, Quetzalcoatl herself can become the sun, a legend where Quetzalcoatl was the Second Sun in Aztec Mythology. Upon activation, it creates a gigantic source of heat, unleashing powerful solar winds from it.
When used in the Babylonia Singularity, while retaining half of her Divinity, Quetzalcoatl's usage of this Noble Phantasm still managed to evaporate a majority of Tiamat's Chaos Tide. Ishtar speculates that had Quetzalcoatl used this on the city of Uruk, the entire city would have been vaporized.