Before the start of history, there were three hyper-dimensional beings of immense power known as the Choujin. These beings apparently created the known universe and existed for the most part outside of it. However, they became concerned with the possibility that there could exist a force or being more powerful than even they were. Unable to tell if this was the truth or merely a flaw in their near-omniscience, the three set out to try and create or discover such a being for themselves.
In pursuit of this knowledge, one of the Choujin sealed away her memory, placed all her power in three gems and became human. This is the woman that would become Washuu Hakubi. Washuu still had many innate powers, an effectively immortal lifespan and an intellect that far exceeded the mortals around her. She founded a galactic scientific academy and devoted her life to studying the "secret" of the three gems. It is known that sometime during these years she fell in love with a man and had a baby, both of whom were taken away from her for political reasons. This prompted Washuu to assume the appearance of a young child, since she no longer cared for adult concepts.
Washuu was working with an assistant named Kagato when she created the mighty ship Souja, Ryo-oh-ki and Ryoko. However just as she finished these projects, Kagato betrayed her and somehow sealed her inside the 'mirror universe' of the Souja. There she remained until she was eventually freed by Mihoshi, shortly before Tenchi defeated Kagato.
Washuu is a capricious creature, with very mercurial moods. She comes across as a bit overbearing in many cases, while simultaneously trying to appear as cute and likeable. She is very proud and frequently extorts her own virtues, particularly her genius. She is also not above mocking and teasing others and likes to play pranks and inflict 'amusing' little torments on her friends and her enemies. Despite her unpredictable nature, she does have a lasting affection for Tenchi, Ryoko and the other members of her surrogate family and will go to great lengths to protect them.
Washuu's powers are all but infinite. While she doesn't have access to all her supreme Choujin powers, she does have a wide variety of innate abilities. She doesn't habitually use them, instead preferring to rely on her hyper-technology. In fact, it is debateable which powers she displays come from her own innate self and which from the various devices she has access to. It is known she can fly, teleport, create energy blades, change her apparent age and other feats at will. By far her greatest asset is her intellect. Washuu claims to be the greatest scientific genius in the universe, and few could dispute that claim. It is probably safe to say that with time she could develop a device or technique to deal with virtually any situation.