What? Have I Been This?

On the hilltop was a wolf, shifting in the leafy light. Its stare tore mine, enriching my already heightened fear. It became me, but older.

"You will find me inaccessible," it said with its constant stare, shifting with the leaves in the forest light like a sun beam caught in water.

"What are you?" I asked. My image roared with a toothy mouth, and faded into a pool of slippery mist. "Dare you discover?" the mists asked.

Entering, an unseen hand handed me sword, simply designed, its edges glowing with a sinister hot white. "You used this. You are changed."