Army of One (Army of One #1)

Could one girl be the key to uniting a world split by an ages-old prophecy spurred by Brother Havoc and Sister Fortune?

A thousand years ago, a mighty battle pitched two of the greatest sorcerers against each other, Brother Havoc and Sister Fortune. In the end Brother Havoc won, shattering his rival into a thousand shards.

Now, a millennia later, teenager Carrie Taylor not only learns that she is one of these shards, but that each shard created an alternate universe, with multiple versions of her out there-and a great evil is bent on destroying them all.

Carrie must team with a handful of "alternate" Carries from across the universes to fulfill a prophecy that will bring Sister Fortune back from limbo to defeat this evil, but the more Carrie travels from broken universe to broken universe, she realizes she might not be working for the "good guys"-nor, perhaps, is she one of these shards after all.

If that is indeed the case, then who is she?