Seiya, as (s)he is known, came from Kinmoku, where (s)he served under Princess Kakyuu and lived with Yaten and Taiki. Galaxia attacked, and they fled, Princess Kakyuu disappearing. They came to Earth in search of her, and becoming an idol singing group, the Three Lights, so they'd gain more visibility and hopefully she'd hear of them. Seiya became the lead vocalist, music composer, and lyricist. They attended Juuban in the same class as the Inner Senshi there.
In both the anime and the manga, Seiya is rather arrogant, rude, and quite sure of his/her skills. (S)he loves performing, but gets frustrated with frequent practices. Usagi reminds him/her of Kakyuu, and (s)he tries to win her affections.
In the anime, Seiya is a man who turns into a female Senshi when transforming. He loves sports, and is actually respectable to other athletes. The Starlights are never killed by Galaxia, and return with Kakyuu to their home at the end.
In the manga, according to reports from Naoko Takeuchi's appearance at a San Diego convention, the Three Lights are all females. The Starlights are killed by Animemates. All the Senshi's spirits are sent to their planets and are reborn, so we have to assume the Starlights were, too.
Seiya has long black hair, which (s)he wears pulled back into a thin ponytail. His/her eyes are a smoky blue color. (S)he wears small hoops for earrings. (S)he's of average height. When (s)he isn't in school uniform, (s)he wears men's clothing, especially suits.
As Starfigher, her powers are drawn from Kinmoku. Her fuku is a black leather bikini top, shorts, tall gloves and boots. She has a sky blue belt of sorts as a choker, with matching ones on her arms. Her tiara is a thin gold line with a gold star in the center, with gold stars for earrings.
Seiya's okay... (S)he can be funny sometimes, but is rather obnoxious most of the time. Too much attitude. I like Starfighter, but as Seiya... very so-so... don't really like him/her.
Senshi Name: Sailorstarfighter