The Sand Band is as far north as any of us have ever been.
There is a point in the desert where the shrub-land suddenly gives way to endless stretches of pure, white sand. This is no gradual progression, no naturally occurring quirk of the geography - there is a very deliberate line in the sand, past which nothing grows. Over the years, the more superstitious of us have supposed that some ill spell had at some point befallen the Band, but to say that the land here is cursed would be an under-statement.
It is never immediately clear that the Sand Band poses any kind of threat, which is precisely why so many have succumbed to it. If one watches the horizon for long enough, it is entirely possible that one may witness a gargantuan shape arcing across the dunes, breaching from the sand only to dive back in like some sort of especially horrid fish. Many a novice scientist has posited the idea that great eels live beneath the sand and swim in it as though it is water, swallowing up any who cross their paths. This is not exactly the most intelligent notion. As anyone who has been dragged through the desert by a particularly over-enthusiastic mount can tell you, sand is not any-thing like water, and is, in fact, extremely rough. Any such creature that attempted to swim in sand would make a powder of itself after the first league or so.
Rather than believe that the sand is inhabited by monsters, I think some-thing different; it seems to me that the sand itself is the monster. This is not the work of any mere corporeal beasts - the Sand Band is possessed. It would certainly explain why nothing ever grows here. The land is always shifting and changing shape, borrowed by the spirits that inhabit it. And too, it would explain why they seem to descend upon a fellow and destroy him as soon as he sets foot in their domain.
While these large-scale possessions do occasionally happen by nature, the Sand Band is far too enormous and clearly defined to have occurred on its own. Some-one put this here, and what-ever is on the other side, they did not intend to let any-one find it.
So, naturally, I have to.