Several millenia ago, Washu was one of the three goddesses of the Tenchi universe, and sister to Tokimi. It's not certain why she does this, but Washu enters the lower dimensions of the Tenchiverse of her own volition and loses any memories she once had of her existence as a goddess. But from what we can tell after watching the Tenchi series, it's safe to deduce that she goes on enjoying life as a mortal =Q

While a student at the Galaxy Science academy, she falls in love with a classmate and bears his child. However, since his parents pass off Washu as someone of low social class, they separate the future mad scientist from her offspring. Washu decides that if lineage and status are all adults judge each other by, then she'd rather remain a child forever. This is how she comes by the resolution to halt her body's aging process and live out the rest of her existence in the form of a twelve year old.

Washu's innocent appearance is at odds with the powerful intellect that she exhibits episode in and episode out. There is no IQ test in existence with which to measure her intelligence. In fact, working as an independant scientist, Washu gives rise to a plethora of ingenious creations. Among them are Ryoko, who goes on to become an infamous space pirate, and Ryo-Oh-Ki, the lovable cat-rabbit hybrid who can revert between cabbit, humanoid and spaceship forms. Though her scientific ingenuity has few bounds, there's still one thing that her knowledge cannot aid her in accomplishing: the extraction of Tenchi's semen. Mental prowess aside, however, Washu is also quite the psychokinetic; she can conjure up a virtual computer and use it to obtain information or advice on how best to proceed with her party's current course of actions.

Although she may appear to be the mad scientific type, she's more down-to-earth than one would expect. As the only real source of maturity and leadership in the group, Washu serves as the icing that holds the gingerbread house together.