So, here's a character:
Name: Xerah Faye Zanarius (Can it get any more 'exotic' sounding?)
Magical ability: Focused on healing
Style: While her method of spellcasting leans towards shamanistic rituals, her spells possess a "gem" motif-wounds are covered by a diamond weave as they magically close, a shield appears as a sapphire cocoon, a 'fire' is actually a large, glowing ruby. These gems fade when the spell is completed.
Personality: Incredibly shy and insecure, Xerah is slow to open up to anyone, as her demonic soul drives her to grab, mate with, and drain anyone she meets. She is also easily scared and 'jumpy'. Occasionally tends to be angry, especially in the mornings, as her mind and soul are in constant battle.
During times of incredible stress, she changes. She becomes more assertive and aggressive, lashing out with magic and demonic claw, intent on protecting her allies and destroying her enemies. She does not become brainless, merely driven. Since this change in personality is marked by a shift in appearance (see below), many wonder if they're not seeing two different people.
Appearance: As a succubus, she has mastery over her appearance, and uses it to look as plain and unassuming as possible. No matter the situation, she makes herself into a face in the crowd, to the point where anyone trying to remember details can only come up with "she was just sorta...normal looking". At the Academy, this tends to be a slim build of average height, with fair skin, brown eyes, black hair, and small breasts. Her clothes also continue this 'average' look, she favors neutral colors and simple shoes.
When she shifts into Demon Xerah, however, her body becomes much more memorable. Her hair turns a silvery-white, her skin turns blue, and she grows a tail about three feet long. Her body also becomes far more voluptuous, as her soul's nature as a succubus spills forth. Anyone can remember this form quite easily.
Bio: Plenty of kids are born not wanting to be what they are. Xerah was born not wanting to be a demon. Slightly different from the aforementioned children. As she progressed through a difficult puberty, her nature as a succubus threatened to overwhelm her at every turn. Her mother did her best to teach the child, but her ability to learn how to control herself was limited by how much Xerah hated what she was. Her mother had the idea to send her to the Academy, where Xerah has picked up healing magic and is slowly starting to learn that being a demon isn't so bad after all. Still has a long way to go, but hopefully she gets some friends along the way.