Globus Cassus

Globus Cassus is the name of an Externian urban legend that somewhere in the Archipelago there exists a purely mechanical Exo.

In the real world
The real world Globus Cassus was a proposal to turn the Earth into a nearly Saturn-sized mechanical object. This never came to plan as it is generally stupid.

In Latin, "Globus Cassus" means "group bought". That's probably not what it means, but whatever.

Appearance
Globus Cassus is chalked up as a purely robotic and mechanical Exo. Having lost it's faith in Externian humanity, GC presumably turned themself into a mechanical being to reject life. How GC has survived is unclear, but considering it is a robot, who knows.

Personality
GC is implied to have lost every last one of their emotions in the period of time when they turned into a machine. As such, GC has a monotone personality according to many mythos.

GC is implied to destroy things for fun in some mythos.