Wolf In Sheep's Clothing

Emala Guthrie is a 17 year old girl. She faces many of the same issues other teenagers face - homework piles, discriminatory teachers, boys that won't take no for an answer. But she also faces a problem no one else she knows has to deal with.
Emala has a rare disorder - dissociative personality disorder. She has two personalities, both the exact opposite of the other.
On the outside, Emala is the nicest young woman, with silver eyes, blonde hair, and light skin. Her smile could light up a room, and she has many friends.
On the inside, Emala's opposite, whose name is Zara, she is a mess. Her hair is raven black, her smile is terrifying and awakens a fear inside you you never knew. She would hurt someone without hesitation, even kill and not stop to think first. Zara's eyes aren't a warm silver like Emala's. Her eyes are dark, blood red.
To keep Zara from hurting anybody, Emala locks her away with an enchanted ring she was given by a witch. Through this ring, Emala can also communicate with Zara with mirrors.
But when Zara grows stronger, and the ring's power begins to degrade, Emala isn't sure how much longer she can keep up her charade. Soon, she will have to confront Herself.
But how?