Tsunami is one of the Chousin, three superior goddesses who created the universe, with the other two being Washu Hakubi and Tokimi. She is the founder of the empire of the planet Jurai, patron to its Royal Family, and creator/mother of its mighty Royal Trees.
Tsunami-kami-sama (津名魅神様, Tsunami-kamisama), 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 is greater then they are. In fact, the sum total of creation was started by them after an unknown length of time spent trying to theorize the existence of such a being. They came to the conclusion that a more practical approach was needed. Tsunami, like Washu, descended to the third dimension to conduct her search.
150,000 years ago, a sleeping Tsunami met with the boy who would be the first Emperor of Jurai. Tsunami (in giant form), had been asleep on the planet for so long that she had begun to turn into a tree. Tsunami recognized within him the seeds of what she and her sisters were searching for. She agreed to provide him with her descendants, "Royal Trees of the Imperial Family." These trees are sapient and powerful beings who bond with certain Juraians, providing them with great power and long life-spans. They are also the central core of Juraian ships, acting as their 'heart' and computer unit, far more powerful than anything else, thus allowing Jurai to become a galactic superpower. Tsunami promised to watch over the Royal Family of Jurai as she waited for the superior being that she and her sisters were searching for as well as for the birth of princess Sasami Masaki Jurai whom she was destined to assimilate with.During Ryoko and Ryo-Ohki's attack on Jurai, three year old Princess Sasami fell from a walkway in the Royal Arboretum, into a septic where the royal trees are grown near the roots of the original royal tree,
Tsunami-no-ki. Sasami was fatally injured and Tsunami assimilated with her in order to save her life. Tsunami and Sasami are merging and one day the two of them will be a single being. In episode 19, it is established that the personalities and wills of the two are one and the same; for example, when Sasami fears for Tenchi Masaki's safety, Tsunami must act, even at the risk of a confrontation with Tokimi. When Sasami reaches physical maturity, she will take on the appearance of Tsunami -- supporting the fact that it was always meant for the two to be one.
The largest tree on Jurai standing at 5,000 meters high, the Tenju (天 樹, "Heaven Tree") acts as the Royal Palace of Jurai, housing the current Emperor and his family and the main homes of all of the Imperial Houses, as well as the Royal Arboretum, and much more. It is here that all of the Royal Trees await a partner that they will bond with. Tenju was created from the giant body of Tsunami-kami-sama.
- Main article: Royal Tree
Like -kami-sama, -no-ki is a suffix (this is a formal version. Simply adding -ki is also acceptable), this time meaning that the name is for a tree. After creating the Tenju, Tsunami-no-ki came into being at the very base of the Royal Arboretum. It was from this tree that Tsunami created the first seeds that would become first generation Royal Trees. It is believed that at least ten first-generation seeds have been known to exist, two of which seemed to have been created before she became Tsunami-no-ki. Of these two, one was used in the creation of a battle robot known as the 'Idol' and the other may have been given to someone from outside this story's universe. Details from this time are sketchy at best. When Sasami was injured during Ryoko's attack on Jurai, she landed near Tsunami-no-ki and it was here that they assimilated. Tsunami-no-ki has now been moved to become the central core of Tsunami-fune, its ship form.
Although very powerful, later generations of the Royal Treeships gradually became less powerful as they progress from Tsunami-no-ki. They also lose their 'will' (that is, their minds and/or soul) if they are rooted on another planet. Funaho-no-ki was believed to be an example of this, but the tree did not lose its will because of Washu's powerful gems on the pommel end of Tenchi-ken, the Master Key which provided the tree with power.
-fune is used for names of the spaceships Tsunami-fune is the the most powerful of all ships. Tsunami-fune is able to control all ships of Jurai, since it is from her that the ships' power is derived. Also, Tsunami-fune's defenses are 100% impenetrable by any form of attack in our three dimensions, due to her ability to produce ten Light Hawk Wings. Ten Wings represent the maximum force that can be generated at any one point in our dimensions. Any more would completely shatter the multiverse. Tsunami-fune has demonstrated matter-transportation, multiple-environment generation, energy-based weaponry, and sub-space travel. Tsunami-fune is officially listed as belonging to Sasami. It is unknown exactly when or how Tsunami-fune was created, but it is estimated to be between 700 and 695 years ago. An alternate possibility is that the ship has always existed, but remains hidden except for select periods when Tsunami decides it is needed, although considering the nature of Jurai ships, this is unlikely.
- It should be noted that Tsunami has not gone from one form to another, but that she exists in all forms simultaneously, with the possible exception of the Tenju.
Tsunami is introduced in the Universe continuity in the manga adaptation to the second movie, Tenchi Muyo! in Love: Eternal Memory also known as Tenchi Forever! Six months after Tenchi has gone missing, Sasami travels to Jurai to search for clues. Sasami is taken into a sacred place in the Jurai palace with a girl named Izumi as her guide. Izumi and Sasami pass challenges in order to reach Tsunami, whose power Sasami plans to use to free Tenchi from the parallel world that he is trapped in thanks to a woman named Haruna. Meanwhile, Sasami reflects on her true feelings for Tenchi, revealing that even though she is possibly too young to "even know what love means," she loves Tenchi with all her heart. Tsunami makes Sasami realize that Tenchi will choose who he wants to be with and that she cannot force him to leave Haruna's world. However, Sasami comes to assimilate with Tsunami just as she had done in the official continuity. She reveals to the reader that although the others believe that Washu's instruments are what allowed the door to Haruna's world to be opened, Washu's plan failed and it is actually Sasami using her power due to her bond with Tsunami keeping the door open, hoping Tenchi would choose to return to them...to her.
In both Pretty Sammy series (the OVA and Magical Project S), 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 Sammy.
Personality-wise, Tsunami is very different from her OVA and Manga incarnations. Instead of being very eloquent and courteous, she's shown being more carefree, relaxed, even slightly ditzy and reckless; similar to Misaki and Mihoshi. 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, Tsunami also has 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.