Ryououki is a cabbit: A cross between a cat and a rabbit. Overall, Ryououki personality, traits and abilities vary greatly depending from series to series, but they usually include shapeshifting and a love for carrots.

In Tenchi Muyo! Ryououki, Ryououki is a unique artificial lifeform created by the universe's greatest scientist, Washu. Following an incident later in, she gains the ability to shift to two humanoid forms — a child form and an adult form.

In the Tenchi Universe continuity, Ryououki is not a product of Washu. Her origin is not explained as a scientific experience, but rather as an animal species

In Pretty Sammy series, Ryououki is male and has the ability to talk in the same language as Sasami. His real form is actually of a humanoid boy with physical features resembling a cabbit.