Physics Blog 9 "Eragon...movie version"

So this past weekend, I was watching Eragon, and in one scene, Eragon uses his bow right after exiting the fortune tellers hut.  As he pulled back the arrow in the bow, it got me thinking aobut kinetic and potential energy.  As Eragon pulled the bow back, he was acquiring potential energy, and when he released the bow, he transformed that potential energy into kinetic energy.  While the bow was traveling towards the guys following Eragon and Brom, Eragon says the elfish word for "fire" which causes the arrow to ignite and kill the bad things? i have no idea what they are called.  so in the movie, unlike the world we live in, energy can be created from nothing.