tophgrl14,
I am bipolar and have these sort of rages too. I also feel like there is someone inside of me waiting to break free from his pinned up lifestyle. I assign him a personality, I don't have DID, but its just easier to relate to it this way. I have been know to call him "The Beast" or "The Demon." I have been this way since I was 13 years old (now 36). As an adult,I only "blackout" moments when i'm extremely stressed or very pissed and then all HELL breaks loose (i.e. i want to kill people, literally). I'm able to control the "blackout" spells but not the rage and the thoughts of harming others. My therapist is even scared to talk to me about this part of my life, sort of weird since he is "Abnormal Pshychologits."
There is some hope though, my meds help control the swinging effect. It doesn't help for the anger built up inside, but it will keep you calmer to where you can at least think before you act (most of the time).
Keep sharing.