Tsunami appears in the OVA version of the anime series Tenchi Muyo!, as its novels (True Tenchi Muyo!) and the manga series written by Hitoshi Okuda. In Tenchi Muyo! Ryo-Ohki and related works she is one of the Chousin, three Goddess-sisters and powerful beings in the story. She also appears in the series' spin-off Pretty Sammy. Here she is a candidate to become the next Queen of the magical realm of Juraihelm.
Tsunami-kami-sama
The suffix of -kami-sama can be literely defined as "spirit lord/lady" and adding it to a name implies a superior divine connection; while kami can mean "god", kami-sama means "God" (such as The Almighty, Kami-sama, in Oh My Goddess!). Tsunami-kami-sama, along with her sisters Washu-kami-sama and Tokimi-kami-sama, were in existence before time and space began, and have spent billions of years working towards locating a certain individual, someone who was greater than they were - how they define 'greater' is a matter of conjecture - but what they would do then is unknown. In fact, the sum total of creation was started by them after an unknown length of time spent trying to theorise the existence of such a being. They came to the conclusion that a more practical approach was needed.
The three Choushin are high-dimensional entities; as opposed to our own three, there are 11 dimensions commonly known to exist within the Tenchi Muyo! OVA. Little is known of Tsunami-kami-samas history before 150,000 years ago. It is known that, due to certain extreme circumstances, Tsunami-kami-sama was responsible for annihilating most - if not all - of an ancient civilization who existed before the Pre-cursor race. Such massive devastation may not seem typical to the Tsunami-kami-sama known today, but she has recently engaged in a minor fight with Tokimi-kami-sama, which destroyed almost a quarter of our galaxy (all damage was later repaired). It must be remembered that the power of the Choshin is far greater than the universe can contain.
150,000 years ago, Tsunami-kami-sama met with the boy who would be the First King of Jurai and recognised within him the seeds of what she and her sisters were searching for. She agreed to provide him with her descendants, Ouke-no-ki or "Trees of the Imperial Family". These trees were sapient and powerful beings who would 'partner' with certain Jurians, providing them with great power and long life-spans. They were also the central core of Jurian ships, acting as power source and computer core, far more powerful than anything else at the time, thus allowing Jurai to become a galactic superpower.
In the Pretty Sammy series, Tsunami is one of the candidates to be the queen of Juraihelm. After she was chosen, she chose Sasami Kawai to act as her representative on Earth. In doing so, Sasami became known as the magical girl, Pretty Samy.
Personalitywise, Tsunami is somewhat more like Mihoshi, a more carefree, relaxed, even slightly ditzy. For example, when she and Sasami first met, she had mistaken the music of Mozart for Beethoven. When Ramia used a cheesy-looking doll to stand-in for her during the episode involving Bif Standard, Tsunami actually thought it was the genuine article.
Tsunami is also clueless about Ramia's efforts to derail her chances to be queen of Juraihelm. When Ramia had disappeared after a caper went wrong, Tsunami, who was grief-stricken, put up posters asking for Ramia's return.
In Magical Project S (Pretty Sammy TV), Tsunami is much the same as her series counterpart, except now with a great love for flowers; in fact, one of her goals as queen of Juraihelm was to "plant flowers across the entire galaxy". Despite this, she eventually managed to win the candidacy.