Critique my OCs!, For a book.. Options

[Strawberry]

Name: Nelly Ashtear
Age: 17
Gender: Female
Race: Human
Occupation: College Student

Birthplace: Wymon, Ohio
Birthdate: August 13
Current Residence: 129 E. Ashton St. Wymon, OH

Hair/Eyes: Pink (dyed)/Blue
Height/Weight: 5'1"/121 lbs

Abilities: Excellent chef and baker, genius-level intellect
Powers: None
Weapons: None

Background: Nelly was born to Sirius Finn and Yvette Finn-Ashtear. Yvette had been previously married, and already had a child - Illenia; Nelly's older halfsister. After the disapparance of Sirius, he seemed to be instantly replaced by Yvette's previous husband - who came back.

As Nelly continued to grow, it was apparent that her intelligence quickly grew as well.

As she entered high school, she dated a young man known as Zander Graham. Nelly tried her hardest to stay with him, but in truth, she was afraid of him hurting her - like Dario did. Eventually she broke up with him.

Personality: Nelly is a shy young lady, often clinging onto her older sister Illenia. Usually seen with a smile on her face, Nelly hides her past behind her, and tries to press forward with positive energy.

Nelly has a large fear of men, because of Dario's abuse towards her. She also is addicted to sweets, and will eat them when nervous or scared.

Trivia:
* Her favorite animal are rabbits
* She is studying the culinary arts
* Although Illenia seems more intelligent, Nelly actually rivals her sister
* Nelly enjoys playing video games - only single player, though

***************

Name: Illenia Lucia Ashtear
Age: 22
Gender: Female
Race: Human/Demon
Occupation: College Student

Birthplace: Wymon, Ohio
Birthdate: September 30
Current Residence: 129 E. Ashton ST. Wymon, OH

Hair/Eyes: Dark brown/Blue
Height/Weight: 5'5"/137 lbs

Abilities: Genius-level intellect, expert in robotics and computer programming
Powers: Touch of Death
Weapons: Pistol

Background: Illenia was born to Dario and Yvette Ashtear - their first and only child. Two years after her birth, Dario walked out on them. Several years passed before Yvette married again, to a man known as Sirius Finn. Illenia then gained a new member of the family, a sister; Nelly.

However, the marriage did not last long, as Sirius went missing. Shortly afterwards, Dario returned to claim his family back. It did not take long before Illenia found that he was a tyran to her, and especially to Nelly.

She tried to protect Nelly as best as she could. Things she would touch would die, so she wore thick gloves at all time to avoid killing anything. She became reclusive.

Personality: Illenia is best known as stoic and uncaring towards others. She is very smart, and knows how to handle herself in many situations. Her soft spot is her little sister, Nelly. She cares for her deeply, and would do anything for her.

Trivia:
* Illenia's favorite genre of music is Symphonic Rock; her favorite band is Sliver
* Illenia is known to snore quite loudly, often waking herself up during her sleep
* She loves to read sci-fi novels - when not studying, she is caught with her nose in a book

***************

Name: Cailou
Age: Over 300
Gender: Male
Race: Werebeast Demon
Occupation:

Birthplace: "Hell"
Birthdate: Unknown
Current Residence:

Hair/Eyes: Orange-Red/Green
Height/Weight: 5'10"/171 lbs

Abilities: Heightened agility and dexterity, able to scale walls
Powers: Illusion, Transformation
Weapons: None

Background: Born in a hellish dimension, Cailou was very different from other demons; instead he was a kind soul who wanted to do good. He was very much tortured for not being like his clan - or any other demon for that matter. .

Cailou somewhow escaped to Earth. He used his powers of Illusion to live among the humans and redeem himself. However, he stayed close to the girl he had murdered, protecting her, as part of his redemption.

Personality: Cailou is a demonic creature with a strong sense of justice and good morals. He constantly fights the evils that live within his soul.

Trivia:
* Like Nelly, Cailou enjoys playing video games - which something the two will bond over
* He enjoys reading about super-heroes, and often reads comic books

[X-M-O]

Are the differences between the races physically obvious? Or do they all have a human form and a monster form?

[Strawberry]

Hmmm..

Well Illenia looks like a human, because she's part human - but I'm pretty sure she has a demon form (not sure what it looks like). D=

Cailou has pointed ears and a tail (though he looks human to others), but has the ability to transform into a powerful creature under certain conditions.

There are two others, but I'm waiting on my friend to help me (they belong to her).

[X-M-O]

Ah, I see. ^^
Well, I was asking that because I wanted to know if their identities are kept secret, or if everyone in the story knows that demons exist, etc.