Nyx

Also known as "The Dark Continent" or "The Dark Continent Nyx" and likely named for the goddess of night, Nyx is home to the Guylos Empire.

Nyx is Zi's northernmost continent, a land of harsh climates and tough Zoidians to match. Its people are warlike and determined, thwarted only by things like hot, bright climates. They had little contact with the Central Continent until King Helic's plot to unite his people resulted in them attempting to invade; Nyx is cut off from the Central Continent not only by a lengthy ocean (or air) journey, but by a zone heavy in magnetic storms known as the Triangle Daras.

The first descriptions of it in canon are of a cold land, full of "tundras of iron sand" and iron ice to match. Indeed, Nyx is freaking cold and frequently dark/under cloud cover. Going by a lot of boxart, it is also quite volcanic.

Before the Grand Catastrophe, the shores of Nyx were guarded by the Bloody Gate, a swarm of stone pillars followed by unpleasant swamps. These, in turn, led to a great crevice known as Godcry, connecting to a veritable maze of ashen terrain full of valleys appropriately dubbed the Devil's Maze. Its capital, far farther north, was named Chepin, and the Republic's fight to reach it was a bitter affair indeed.

The Catastrophe was hardly kind to the continent—large amounts of it sank under the ocean waves, leaving its old southern border gone and the Devil's Maze a mere shadow of itself apparently renamed "Mazemercy". The Triangle Daras expanded, making direct travel between it and the Central Continent even trickier. Nyx's people themselves held together, however, and some of the Guylos army would even team up with the Republic after Prozen's Neo Zenebas coup attempt destroyed their remade capital city, Valhalla.