[hider=appearence] [img=http://4mchan.org/Forum/gallery/102_03_12_09_11_44_32.jpeg] [/hider]
Name: Oona Fredrick
Age: 16
Gender: female
Species/Race: Selkie
Powers: can change form into any water based life-form (within reason) mainly fish and the like, if she has a piece of the creature (for example if she wants to become a trout she needs a trout scale, or a sea turtle she needs a claw or something. Only water based life-forms! and she can only take on the form of magic sea creatures, mermaids, naiads, ext, with the help of one of those creatures (in other words she needs a live, and willing, mermaid there to take the form of a mermaid) but she doesn't have the powers of those creatures (control of water for Naiad or whatever) just the physical attributes, however can come in useful because she becomes the natural size of the creature as well. she doesn't require anything to turn back into herself
Weaknesses: fire of course, doesn't get the powers of magical creatures she becomes, has to have something of the creature to become it, poisons affect her more then they would a human, and anything that can kill a fish can kill her. She HAS to get into clean water (chlorinated doesn't work) every week or so or she begins to dry out and can lead to death very quickly, (can substitute short dips and sponge baths and the like but requires it far more frequently if she does so)
Personality: a generally very active and friendly girl, likes to show off her powers, but doesn't get much chance as anything worth showing off (like a whale) is either hard to find the object required to change, or she can't find a space big enough. She is also very protective of her friends, some times it appears clingy, which can turn people off from hanging out with her too much, She is a very happy-go-lucky kind of girl. she isn't very good with technology but would like to learn more about it (hence the reason she's taking computer class)
Background: Her mother was a selkie but her father wasn't (there are no male selkies) and her mother had 3 boys before her, none of which had powers. Her mother doted on her and she was her father's pride and joy, which caused her brothers to resent her, she didn't realize this till she was a teen and the boys started playing dangerous pranks on, After one particular prank landed her in the emergency room and there were too many questions about the girl that she couldn't answer the family moved and Oona was sent to Athalia, to protect her. 
Study: the main 4 classes, computers, swim ;), and sculpting
Theme:
[youtube]LbgyL-QOreI[/youtube]

(this is a slightly modified version of the mythical selkie by the way, normally selkies have one skin that changes them into just a seal, but this isn't much different and will be more fun to play, i hope you don't mind)

and i'm allowed to have 3 characters :D (didn't know if you just wanted me to answer or restate the question)