Mizumori Mio
This is Mizumori Mio, our heroine. She's a typical Japanese schoolgirl (as long as you don't talk about the way the water in her fishtank seems to react to her moods).
An only child, her beloved parents are killed when the apartment building she lives in blows up in a freak accident. She's the only survivor of the entire block, so she goes to stay with her only known relatives - her distant cousin, Sijoh Tadaomi and his family.
So the fact that she does cry rather easily in the chapters following the tragedy shouldn't be held against her. She gets a backbone in the second book, and when she does...!
Sijoh Tadaomi
To our right is Sijoh Tadaomi. Mr. Sijoh's
also a psychic, but unlike Mio, he is aware of and able to consciously
use his power over Fire. He is also extremely ruthless and has neither
compassion 
nor
empathy with his fellow human beings (when he is feeling angry or thwarted,
he goes out and blows up fuel trucks. As they're driving down busy streets,
surrounded by traffic. Nota nice guy). In fact, he blew up
her apartment.
You see, what Sijoh Tadaomi wants, he gets. And what he wants is Mio.
Narumia
Rei
Narumiya Rei is the school's golden girl.
She's good at schoolwork and sports, and if she's a little standoffish,
that's okay. She's so cool, nobody cares.
But she really is a he, and
his real name is Narumia So.
When he was just a small boy, the Narumia
family home was set afire. His family, being priests, had recognised that
their son was a psychic who could control Air. They also recognised
that the fire could only have been set by a fellow psychic, who could control
Fire. It was clear that the fire had been meant to destroy their son, so
they told everyone that their daughter, Rei, was the survivor.
Naturally, such a deception, however necessary,
leads to such things as frustration and hidden love, as So must deal with
the fact that he's attracted to Mio, but she thinks that he is a
she....