Washu's age exceeds at least 20,000 years. Despite this, she looks like a child and uses this to get out of work. She takes the form of a twelve year old most the time, but also has the capacity to look fully-grown and mature. She likes to be called Little Washu, and has a very screwed up sense of humor, but she maintains her dignity and, like Sasami, gets close to Tenchi very quickly. Despite her love of being treated like a young girl, she is the greatest scientific mind of the universe. She created Ryoko and Ryo-oh-ki out of a creature known as Masu (Ryoko using one of her ova and Ryo-oh-ki from a nutrient body) and a ship called the Sousha that is amazingly complex. One of her students at the time, Kagato, stole the ship and put Washu into a prison in the other dimension of the ship. Mihoshi broke her free and Tenchi saved them from Kagato.
When Tenchi's baby cousin, Taro, visits them, Washu takes to him as a mother. During this time, we learn that Washu has had a baby before with a nobly born man. When the man left her, he took the baby and broke her heart. She is still sad about it, but she sees Tenchi as a "pretty nice guy" and sets her heart on him. She also uses him as an expirement from time to time. Sheconducts these expirements from her sub-space laboratory. The laboratory has been in place for many thousands of years, but she conected it to a doorway under the Masaki's house. The lab has five planets, one in the middle surrounded by the other four.
Washu is a Goddess from another dimension. She came to this world of her own free will, but she does not remember her previous time as a goddess as her memory of that was sealed in the three Gems that Ryoko uses. She is related to Tsunami and Tokimi.

The Trinity
Washu is one of three other-dimensional Goddesses that have a hand in our dimension. Washu was a goddess until she chose to come to our dimension of her own free will. She retained her vast knowledge of all things, making her the greatest scientific mind of the universe. However, she lost her knowledge of being a goddess when it was wrapped into the three gems that Ryoko uses for power. Tsunami is believed to be the creator of all life, starting with the Juraian trees. Tokimi, jealous of her sister Tsunami, tries to destroy all of her sisters work.