Suou is the Princess of Radiant Garden in the Kingdom Heats fanfic Darkness and Light, and the former Princess in the fanfic Reigning Shadows.
When first introduced she is described as wearing an elegant dress, as she is dancing in the castle ballroom. She also is described as having long black hair.
By the time of Reigning Shadows however, due to the fact the Empress has control over Radiant Garden, she instead wears a similar outfit to what Tamashii wore in Darkness and Light, except in blue.
It is revealed that she knows of the different Noble Names within Radiant Garden, as she has been taught the Radiant Garden history since she was young, the Heroes are suprised to learn that Blaid's family line was noted out of the top ten Noble Families of Radiant Garden whom dissapeared after the 2nd Great Keyblade War. It seemed that Blaid's family line, upon being kicked off their throne in the Realm In-Between after the 1st Great Keyblade War, were welcomed into Radiant Garden as one of the Noble houses.
Suou's name is based off of Suou Pavilochinko from Darker Than Black: Twins of the Meteor (also known as Darker Than Black Season 2)