She is named after
the famous space pirate who attacked Jurai 700 years previously (yes, that
Ryoko).
She is capable
of shape-shifting, able to change her outward appearance to that of another
species (she even transforms herself into a mermaid in one episode). Little
is known of the nature or origin of this ability, however.
Ryoko's Japanese
voice is provided by Aya Hisakawa, a veteran voice actress and singer whose
major roles have included Kero in Card Captor Sakura, Skuld in Oh
My Goddess!, Yuki in Fruits Basket, Minamo "Nyamo" Kurosawa
in Azumanga Daioh and Sailor Mercury in Sailor Moon.