Prologue: Controlled

An elf ran across a field with all his might. He was running away from a spell, but he didn't know where he was going.
The elf reached the Dark Forest. He did not know why he was running; his mind was not itself.
The elf was being controlled, which he realized soon enough. The worst part of it was that he had no idea where he was going and why.

The thought of being controlled sickened him as if he was going to die. Being under the control of someone he hated the most, and not being able to do anything to stop it, was worse than death for the young elf.
He could not think straight; all he could do was run, until he suddenly stopped on a hill.
There on that hill, he saw a beautiful kingdom with many gorgeous, giant towers, miraculously colored gardens, and the most awing sight of all, the castle.
The castle gate was about fifty feet tall with at least forty-five guards surrounding it. The gate was made of the most marvelous stone he had every seen.
The exterior of the castle was also made of the extraordinary stone.
It was nothing like he had ever seen.

Unwillingly, he began to walk to the gate. But the spell was so strong; he could do nothing but keep walking.
What was he doing?

And most important of all, what was he about to do?