Magicant Theory

Maria’s mind became psychically linked to the Earth as a whole, which caused the Eight Melodies to be scattered across the land out of her mind. Additionally, while the appearance of her Magicant was fueled by her mind, it was a real location in the depths of Earth’s underground. After her mind passed on from hearing her song pieced back together, the location of Magicant became void but still tied to the Earth.

This caused a new eight-part melody to be spread across the world. It was from these Sanctuaries that Ness was able to recreate the new song and reshape Magicant from his own mind. Formed in the same location and from the same essence as Maria’s, it shared many similarities such as bright colors and the Flying Men. However, upon defeating his Nightmare and absorbing the Earth’s power, Magicant was undone yet again.

The physical location of Magicant corresponds to what is known as the Cave of the Past, as evidenced by the same metallic tentacle as the warp to the Sea of Eden, at the end of a spiral-like path. This location was Giygas’s choice for a base because it still retained a connection to the mind of his adopted mother, Maria.

- Miles of SmashWiki