[@Sorrelmyst]

Not sure where you got schizophrenia from, as you haven't mentioned anything like that in your CS. As for "Dual personalitied", it doesn't exist. What I assume you're referring to is Disassociative Identity Disorder, of which a person suffers from a disassociated state of mind and multiple personalities. As any web source will tell you, DID isn't as black-and-white as having two people struggling for power in one's head as your CS states. Typically, DID patients will create a secondary personality, or "Host" personality in the event of trauma. These personalities are typically innocent and unknown to the trauma they sustained, as the sole purpose of it's subconscious creation is to protect one's mind from trauma: It's an extreme form of denial. It's rare for DID to create aggressive or violent personalities, and more often than not any violence brought forth from the Disorder is internalised - they'll attack themselves, hate themselves, etc., rather than hurt others.

It should also be mentioned that sufferers from DID nearly always suffer from other forms of mental issues on top of it; Amnesia, Anxiety, Depression, Self-Hatred, suicidal thoughts, in some cases Agoraphobia... the list goes on. 

Basically, what you need to keep in mind - if you are having you character suffer from DID - is that it's an illness. It is not good, and it does not bring with it good things; it should never be written as convenient, as a super-power, or for a plot-point. It's unfair to those who suffer, and doesn't help in stereotypes.

This [url=http://www.nytimes.com/2005/10/01/arts/dealing-with-the-nightmare-of-containing-multitudes.html]interview[/url] with a sufferer of DID describes the disorder rather well, if you're interested in learning more.