Okay, I made a few assumptions, so tell me if they're wrong.
1) It's spring, so Zora is just finishing her first year of high school. (Could be second, though)
1.5) It's a three-year high school (if this is wrong, just add one to the above)
2) Demons are typically malicious.
3) Each kami has their own shrine.
Name: Aria Sutar
Gender: Male
Age: 17
Species: Tame Demon
Personality: Fun-loving and feminine. Aria lives his life as a girl for the most part--with notable exceptions. There are times when Aria will be frighteningly aggressive, and almost all of them involve Yui-chan.
Bio/history: Arion ran away from home. There were some specific reasons behind it, but in general he'd gotten fed up with living among demons. He couldn't run away safely alone, though, so he ran to Aiko (rumors set her up as a generous sort). In exchange for his promise to behave, Aiko granted him her protection. She isn't so foolish a kami as to simply trust a demon's word, though, so Arion was enrolled with Zora where she could keep an eye on him.
Along with abandoning his life as a demon, Arion changed his name. He became Aria. While he was changing things, he decided to revamp his personality. Still technically enrolled as a boy, Aria is generally treated as a girl; nobody looking at him would believe otherwise. The school has had a year to adjust to Aria; in that time he has become fairly popular with both guys and girls. At first it was a bit awkward--he's attractive, just more to the wrong gender--but that issue was settled when he found a girlfriend. Now that they know he's taken, everyone can speak with him on friendly terms without being conscientious about whether it's okay to think he's attractive.
Appearance: Aria stands at 5' 5". His hair is a light brown, his eyes a sparkling blue, and his skin is supremely fair. He has no body hair and wears a padded bra to complete the effect.
((Note: I don't know how I'm going to handle pronouns yet. I had to keep erasing 'her' and 'she' even writing this.))
Name: Yoshida Yui
Age: 16
Species: Human
Personality: Timid and quiet--everyone who has described her since grade school has used these words. Now in high school, a few people are beginning to notice a quiet determination in the girl. It started after she met Aria and has been slowly building.
Bio/history: Yui comes from a remarkably average family. Her sister, Haru, is in middle school; her mother is a housewife; and her father is a government scientist. From these humble beginnings came an even more humble girl. Yui doesn't wish to excel, neither does she allow herself to fall behind. She is very soft-spoken and her greatest fear is to stand out. She has held back from approaching most people for exactly this reason, so Yui's friends could be counted on one hand.
And then came high school and Aria Sutar. The self-proclaimed boy was having some trouble fitting in with the others (a guy in drag can have that effect). While the other students tried to avoid him, Yui couldn't help but stare. He was very different from her: he stood out, he was outspoken and cheerful, and above all else he was confident. Yui envied him a little. So when she looked up to sneak another peak and found him standing right in front of her, she toppled straight over backward with a quiet scream.
Not a month later the two were a couple.
Appearance: Yui is a tiny 5' 2" and very light. Her meter of hair is naturally white, her eyes silvery-blue, and her skin so light as to be pale. She does not wear a padded bra, so by appearance she's smaller than Aria in every way (except hair length).