Ryoko Hakubi is a main character in the Tenchi Muyo! metaseries. She is a semi-reformed space pirate who is madly in love with Tenchi Masaki, the main protagonist. She is always shown to have a very competitive relationship with Princess Ayeka, who also has a very strong romantic interest in Tenchi.

In the Tenchi Muyo OVA Ryoko is a binary clone, the product of combining the DNA from an ova of Washu Hakubi with the DNA of a powerful aquatic lifeform, known as Masu.

In the Pretty Sammy OVA, Ryoko appears as a schoolgirl, Ryoko Orikasa, a yankee. She and Ayeka constantly bicker over Tenchi Kawai's affections.

In the Pretty Sammy TV series, Ryoko appears in the last few episodes starting with episode 23 as Oryo, or "Overly Splendid" Oryo (Bodyguard to Queen Tsunami of Juraihelm. In contrast to Ryoko's usual characterization, Oryo is a dignified and honorable warrior, ready to lay down her life for Tsunami.