Stats
Position: outer senshi sorta, guardian of the Royal Family of Labyrinth (Pasiphae, Styx, and Zephyr)
Element: snow, ice
Fighting Style: offensive (usually, not always)
Secret Weapons: physical strength and mercilessness (if that's a good thing)
Guardian: none
Symbol: 

Appearance
Average height, with light blue hair and darker blue highlights, and black eyes.

Personality
 Little is known about Ciara, since she has only been in her human form for a little while.  But Cypress remembers that, before she got captured by the Death Ladies, she was a kind, generous girl.  But after being possessed, she becomes morbid, egotistical, and basically an unpleasant person.
But after going through the purification process with Sailor Spica, she regains her old personality a little, becomes a human, and gives herself a regular name.  She still has morbid tendencies and an inflated ego, but she's not as bad as she was before being purified.
As Sailor Nova, her attacks deal with snow and ice.  She is mildly agressive (I know that's a paradox, but I meant it to mean that she's sorta agressive, not much though).  She has no mercy for her enemies.  She is also extremely strong physically, and could beat up pretty much anyone.  She could probably even beat the other Sailor Astros while they used attacks!
A bit of explanation about her senshi name (which fortunately isn't a huge spoiler): most of them are named after the stars, constellations, or galaxies they came from, and there's no galaxy named Nova. She was originally called Sailor Okouri, since she was from a star called Okouri, but Okouri went nova in the year she went off to Astro, killing all its inhabitants, including her family. She decided to drop her former name and call herself Nova, to honor the death of her people. (it is later found out, exactly why the star went nova, but that would actually be a huge spoiler)

Street clothes
 She dresses sort of Gothic.  She wears black and other dark colors all the time, and she loves jewelry.  Especially necklaces and earrings.  Her favorite outfit is a dark red blouse with either a long black skirt or a shorter pleated black skirt, and she wears a silver ankh necklace and earrings with it. And of course she wears the same school uniform, but she hates it.

Transformation
Nova Astral Star Power
Nova's transformation phrase.  She says this and holds her transformation wand up.  Snowflakes fly by her and one completely blocks the "camera's" vision.  When it flies out of the way, Nova is magically in her sailor suit.  She poses in front of a symbol of a snowflake.

Nova Crystal Star Power
Her second transformation phrase.  It's like her first one only at the end she poses in front of her symbol.

Attacks
Nova Snow Blizzard
Nova says this and a blizzard of snow swirls around, blurring everyone's vision.  When the blizzard clears up, her enemies are frozen in ice (like Shabon Spray Freezing).

Poison Ice
Sailor Nova whispers this and raises both arms to the sky.  A cloud appears above her and from the cloud snow falls into Nova's hands.  Nova extends her hands toward her enemy and shoots blocks of poisoned ice at them.

Slow Freeze
Nova's powered up attack.  She says this to cause the enemy to freeze over, a little at a time.  Like first their feet, then up to their knees, then their legs, etc.  It's very painful and actually quite cruel, so she doesn't use this except on people she really hates.

Items
Transformation pen
Ciara's first transformation item.  It's like the other Astros' with a gold star on top, but it's red with a black stripe around the base.  The star has a black jewel on one side and a red one on the other.

Transformation ring
Her second transformation item.  It's a gold ring with a blood red, star-shaped jewel on it.

What she thinks of the others
Zephyr: likes her okay, but for some reason she resents Dani a little, probably an effect of the brainwashing.
Vega: likes her, but thinks she's a little immature.
Io: doesn't like her at all, because of her ditziness, and thinks she's not serious enough to ever be really good as a senshi.
Andromeda: Ciara thinks Andromeda is nice, but a little too nice and shouldn't let people walk on her
Inferno: Ciara thinks that Anala's cool, and likes her okay too.
Orion: Hunter has always been nice to Ciara, so she likes him too, besides, she has to get along with him since his girlfriend is her best friend.
Arcturus: Ciara likes Misty, and thinks she's cute and very strong for a little kid.
Spica: Aisling is Ciara's best friend, and she healed Nova, so Ciara thinks she really owes her one.