Magical Metals (also called Blessed Metals) are metals that can be used by Greek and Roman Demigods and immortals to fight against monsters and other evil creatures, as well as gods and other demigods. The Greek Gods and demigods use Celestial Bronze, while the Roman Gods and their children use Imperial Gold. Hades, those who live in the Underworld, and some of his children (like Nico di Angelo) use Stygian Iron. Demigods use weapons made of these metals, because these metals are the only metals by which a monster can be harmed.