Here's a bio for Ryo-Ohki!

Voice Actress: Debi Derryberry

OAV/Universe/Tokyo
Half-cat, half-rabbit, she can take many forms – from intergalactic space ship, to pink mecha-robot, to near human. She is Ryoko’s companion and they share a unique bond. Ryo-Ohki also loves carrots – and Tenchi is always trying to plant enough to satisfy her! She is usually good-tempered unless threatened – and she has a cabbit crush on Ken-Ohki!!

Bio taken from The Official Tenchi Muyo Website