Arisa Rokujou is the main character in the GBA version and one of the three selectable main characters in the PS2 version. She was the lover of Akira Kishi until his death a year prior to chapter 1. The two had known each other since childhood, and she fulfilled her dream of dressing as a maiko when the two were on a date in Kyoto. On November 29th, the day before he died the year prior, she receives an unmarked letter containing a train ticket to Kyoto.
Arisa is a second-year student studying literature at Tokyo University. Even after losing Akira, the son of a former Prime Minister, she is well off enough that she is not looking for work.
She is 19 when the story begins.
CHAPTER 3 SPOILERS
She in fact witnessed Akira Kishi's murder. The two didn't get along as well as she tried to suggest.
EARLY ENDING SPOILERS
She tells Tooru and Natsumi that she is a "newhalf", which was much to Akira's appeal.
DEEP ENDING SPOILERS
However, she is a biological female and was merely lying to those two to protect herself.
She is the twin sister of Rakai.
She is the only appearing character to not be involved in some way with Sun TV.
From Lady Rokujou, a lover of Hikaru Genji (assumed to be a fictionalized version of Minamoto no Tooru) in the Tale of Genji. Lady Rokujo was the daughter of a Minister of the Left, though the modern equivalent of this role was given to Akira.