I like the character and it's very well thought out but it seems a tad powerfull for this kind of format. I have a couple of questions before I would bring a character in the arena against this person. How fast can she change "forms". Also are these different people controling her or is it just that she has a split personality? Because if thats the case how did she become so powerful in each aspect of her power. I'm sure you have heard the phrase "Jack of many trades. Master of none." I've never been a fan of characters that break that rule.
I'm not saying you can't have the character but it's just not something that I feel any of my character can stand up against.
She has four different actual, essences, in her which take control. Switching control is something which takes a serious toll on her and the different parts of her will often fight over what to do. Yes when she's working together she's nigh unstoppable but the day all four of her aspects are in sync is the day I stop roleplaying her. In most fights she'll falter in situations or stagger on a deadly blow. It's literally which ever aspect of her is strongest at that point will be in control and in a combat situation where energy is being used at a rapid rate the switches happen often and can happen at seriously key points causing her to lose momentum.
In regards to how she got so strong, Inshalia and Delanyia are both separate people who, with 4 years of roleplay, were forced into the same body. Delanyia at heart isn't cruel, vile or aggressive and she will usually try to stop a fight, to the rage of Inshalia. The blood rage state and her demonic form are both results of large scale magical events which impacted her and split her already broken mind further while gracing her with powers that make her stronger but also are patchy and unreliable at best. When I used to Roleplay her many people would complain that they were being thrashed and then I'd stagger "just to go easy on them" but it's part of her character. Even if she's losing it'll still happen, just less often because her different aspects have begun to get scared and are more willing to give control.
Hope that cleared stuff up, ask if you need to know anything more!