If you're still doing this, then here's how I first developed my character (I have the format and fill in the details for each character)
Name: Quixel
Race: Demonized Half-elf
Hair Color and Style: Silvery with natural crimson highlights, long enough to cover ears and usually unkempt
Eye Color: Left eye red and right eye blue
Approximate Age: 16
Special Features: His ears are slightly pointed due to the curse, and has cat-like canines. He didn't grow up talking, so he has a hard time forming words; this often causes issues while trying to communicate with his companions. His skin possesses a natural gray tint.
Special Abilities: His red eye allows him to to see magical residue(meaning he can see active spells), and his blue eyes gives him elfin sight and reflexes. Both abilities together allow him to link mentally with creatures of lesser intelligence. He uses this ability to communicate with his companions easier. He also possesses great speed, being able to bound several hundred yards within seconds.
Back-story: To demonize someone, a vapor created by a creature called Gobenon must be inhaled. The required volume for humans and elves is different, because they aren't the same. Quixel was demonized when he was 9 months old, and the human volume was used. Because he is half-elf, the curse didn't take full effect. It only served to change his left eye and his appearance. Since elves have a higher sense of right and wrong than humans, he didn't become the emotionless creature that Gobenon wanted. He was left in the high mountains to die, but was rescued by a giantess, who taught him all sorts of things. He has no memories of the giantess though, and only really remembers the last eleven years of his life. He can understand the common tongue, but acts more like an animal since he grew up around them. He saves an injured elf's life when he's about sixteen, and the two become great friends. Through certain circumstances, Quixel follows this elf and the elf's master to the elfin capitol and his story starts there.
Place of Origin: Unknown where he was born at, but grew up in the forests around the elfin capitol Fallen Star. Lived alone in a small cave north-east of the elfin capitol.