Early on we find out that the Dahaka is chasing the Prince, driving him to stop the creation of the sands, so he won't open them and will get left alone. We also find out later that the Empress is fated to be killed by the Prince. But in that case, why does the Dahaka seem so hellbent on removing him from the timeline before he can kill her and create the sands? Wouldn't that be a paradox? Also, the Sands of Time prince would certainly have just found a way to defeat the Dahaka as soon as everything was explained to him, as he's more then willing to Screw Destiny at that point. Even if the game proceeded as normal, he would have figured out something was up, and would have asked "why am i supposed to kill you?" It turns out that he had already changed the past, so dying before then would indeed have caused a paradox. Otherwise her death at his hands couldn't have been foretold. And she sees all the timeline, so she would know if it was the original. How can this be explained? The Dahaka was not really trying to kill him for most of the game. It was chasing him not to kill him, but to turn him into the bitter man who would be willing to travel to the past to kill the Empress to "stop the formation of the sands" like he is supposed to. And, indeed the Dahaka doesn't chase him while he is in the past, because he is supposed to be there killing the Empress. Once he does that, then the Dahaka attempts to remove him in earnest, attacking in the past. And indeed, that is the hardest Dahaka chase in the entire game. It takes usage of the mask of the wraith to actually cause a real timeline change. The entire first game including the grand rewind WAS the original timeline! Note that this true change of the timeline doesn't end well either, as shown by the next game.
The Mask of the Sand Wraith can only be removed if the "other" self of the wearer dies, allowing them to undo the transformation. In the Prince's case, it actually makes sense. Recall that when the Sand Wraith caused the Prince's past self to die at the hands of the Dahaka, the Mask falls off, reverting the Sand Wraith back as the Prince. Of course, the past self of the Prince died earlier than he was supposed to, which means that all the actions that he would have done is now gone from that timeline, including his chance to wear the mask in the first place. Although it's not explicitly mentioned again at that time, the whole deal with the Wraith can be summed up into a Temporal Paradox solved with a Kill and Replace.
It's pretty obvious that the enemies are all made of sand, and the game doesn't really shy away from it. However, when you consider that both Shahdee and Kaileena turned into sand when they died, it makes you start to wonder... are you the only true living thing on the island?
Except everyone on the island is living... well, in some twisted way. Unlike Sand creatures from Sands of Time, they actually have free will. Now how about the real horror - power source for Prince's medallion?