Karzahni is a nightmare land. Literally. It is the worst place that any Matoran can think of, so terrifying that its name has not been spoken for tens of millions of years; as a result, very few actually know its real name. Those who don't refer to it by the name of its ruler: Karzahni. No one knows what happens there; no one wants to find out. Few legends actually speak of what Karzahni is like. It is said in whispers that the entryway is a barren wasteland, scorched with magma streams and pits of flames, where unfortunate creatures are shipped to other sections of which nothing is known. The land is guarded by a door which none have ever passed through, unless they are allowed. No legend states the location of these doors, but say they are hidden in a place where no light ever shines. But they do hint that the one place that tells of their location is deep underneath a cursed island. And then there is one other legend, one that states that Karzahni is not a destination, but a gateway—a gateway to somewhere else...
But that's just legend. A story told around campfires. A legend written by paranoid maniacs who thought the world would end tomorrow. There's really no truth in it. Karzahni is just a myth.
Isn't it?

Artakha is the polar opposite of Karzahni; called "the Great Refuge" and "the land no shadow can enter," it was a haven for Matoran and other creatures during the first age of the world. Since the coming of Mata Nui, and the estalishment of light and order in the world, references to Artakha have dwindled, and few now believe it to be anything more than a myth.
As with Karzahni, no legends directly stated the location of the doors of Artakha, only saying that the doors are "hidden in plain sight, but will only be revealed when the purpose is served."
Legends also state that the doors of Artakha are guarded by something that "will not suffer any darkness to pass."