Castle Metallix

Castle Metallix is the main headquarters of the Brotherhood of Metallix and Emperor Metallix's home. Being the main headquarters of the Brotherhood of Metallix, it is built in Sonic's image, like most Metallix Troopers. Somehow, it's bigger on the inside, storing hundreds of guest rooms, a giant dining room, and two factories: one that produces Metallix Troopers, and one that produces resources to help annihilate world poverty. This may be because the castle is made out of the nanites Emperor Metallix stole from Dr. Robotnik during his decay into madness, and he has the power to control the nanites.

Trivia

 * On the inside, Castle Metallix's halls and dining room is big enough for the General of the Repliforce. The reason for this size is unknown, even for The Merger Magikoopa.
 * Emperor Metallix is the only one who knows why he made the castle that big, but he refuses to explain why. It might be so his Titan form could freely move around the castle.
 * Since the castle is so big, it's always filled with beings, mostly Metallix Troopers, to prevent a feeling of emptiness.
 * On the outside, Castle Metallix looks like the castle ruled by Sonic the Comic's Evil King Sonic.
 * The idea of Emperor Metallix having a castle, as well as the fact that Castle Metallix looks like it's made out of stone, is inspired from Sonic Heroes. As such, Castle Metallix bears some similarities with Hang Castle, NEO Metal Sonic's castle.
 * Ironically, Final Metallix's design is inspired from NEO Metal Sonic.
 * Furthermore, Castle Metallix's theme is the theme that plays in Hang Castle, when the gravity is inverted.