zodiac sign: Leo
favorite color: Yellow, pink
race/ethnicity: Part Hispanic, all dead
likes: Gossip, shopping, clothes, girl stuff, people to talk to
dislikes: Loneliness, seriousness, schoolwork
talents: Talking, spreading information, filming
transformation phrase: ghoul power, make up!
transformation item: Gold cross earrings
attack phrase: ghoul order: cogito ergo sum!
weapon: Nothing, but she has the ability to think, which for a ghoul is pretty impressive
When Kim was alive, she was the school's biggest gossip, friendly and talkative but always out for a story. She was never the best student, but she was pretty handy with a video camera. Her father runs a local tabloid, and she wanted to break into the business early. Though generally liked, she was never trusted except by the most naïve of people: she couldn't keep a secret to save her life.
Then she made the fatal mistake of trying to film the actions of a vampire while Integra and Alex were on the job. After destroying her film, they discovered that she was destined to become a Sailor Knight as well. Turns out a prerequisite for becoming Sailor Ghoul was to become a ghoul herself - by being the masked vampire's midnight snack.
Kim is currently a walking, talking (though all in lowercase letters) dead girl living in the Hellsing mansion. Her order is the power to retain her mind, making her more like a low-level vampire than a ghoul (which is just an animated corpse), but she is a ghoul nevertheless. No matter how fashionable the clothes over it, her cold, grey skin and hollow eyes mean she can never go home.
Anyone else would be deeply depressed by this. Kim is either too cheerful or too airheaded for that. (Nobody is quite sure which.)