The following is an exceprt from an old vitasophy scroll - and ancient school of thought considering what magic meant. Often dismissed as fools situated in ivory towers, some of their assumptions of magic have proven to be eerily preminiscient.
Everything has its time. Everything has its choice. This is the nature of reality. Everything that can happen, will happen - but we are doomed to see only one of the multitude of possiblities.
Time is a complicated thing for a person to understand to its full extent. Naturally, what we think time is, is much simpler. It's a straight line - no, an arrow is a more accurate assumption. It only goes forward[i], as it wishes, impossible to beat or slow down. And we are doomed to travel along that line, inexorably. This is our conception of time. It is based purely on what we know, what we can comprehend.
Sometimes, advanced spellcasters will look at time, and ask - why [i]must it move forward so quickly? Could it not be slowed down, sped up... stopped? The search for a means to control the speed of time's flow can drive people mad, and the answers are not uncomplicated. But yes, time can be sped up, slowed, stopped. There is a question raised by this. Is it truly magic, or simply understanding of what reality is, that gives a man this ability? Is the earnest belief that time will stop, embalmning him in its caccoon the true reason it does so?
This is what we know and understand of reality-shifting, as it regards to time. This is what we have seen. But we must consider so much more than this. For when the universe was created, time may have been a linear straight line, every step calculated and predicted, for millenia. There was no way for the future to change. Everything that happened would be predictable. But then, Ao saw the world of Aeria, and he created beings of thought. Of free will. Elves, humans, dwarves, goblins... they all had the ability to make an un-predictable choice.
And then the nature of time shifted.
While the past is set, unchanging, the future is a many-faceted path of choices. Every decision a person could make creates a new reality. If one was to shift forward in time, who is to know which one of these possible strands of time you will end up in? It's the essential flaw in time travel, one many reality-shifting mages killed themselves trying to solve. For if you drift forward in the future, who is to tell which future you see?
But there are some things we do know. For one, a person who leaves their time does so permanently, forever pulling themselves from the ravages of time, forcing themselves to live a long life, doomed to drift through realities. Despite this, the few who have not killed themselves from the sheer insanity of travel report various things. A pull, an indescribable drawing, to time as it should be, the correct time. They say that while they can travel back in time, they cannot change this 'correct time', that it has an inexorable pull. It is their anchor, where they would be had they not cursed themselves to drift forever.
This is the curse of one who transcends Time and Reality.