Masaki is the reason her brother came to find the Chousin goddess Tsunami. They got into a disagreement of some kind and she ran away. Her brother went to find her and stumbled upon a sleeping Tsunami. Tsunami saw that the man's descendants would produce the higher power that she was looking for and gave him the seeds of what would become the Royal Trees, granting Jurai's Royal Family great power. However, her brother did not want the responsibility of being emperor of Jurai, and he planned to push leadership onto Masaki and run away.
However, Masaki was a bit too clever for her brother and with her Royal Treeship, she ran away instead by embarking on an exploration quest. It is Masaki who founded Earth and registered it as a colony of Jurai. Masaki apparently gave birth to at least one child while on Earth.Centuries later, the current emperor Azusa Masaki Jurai, was sent to Earth by Tsunami after a battle with Kagato. Azusa discovered that Masaki is still alive in astral form on the dark side of the moon. Somehow, Masaki's ship crashed on the moon through unknown circumstances. She is currently dead, but because of her connection to her Royal Tree, she continues to remain in astral form.
Years later, Masaki ends up meeting the son of Tenchi Masaki who also ran away from Jurai. While he talks about his problems with his overbearing mother, Masaki complains about her brother. Eventually the two fall in love, realizing how much they have in common. The goddess Tokimi gives Masaki her body back and when Tenchi's son grows up, she marries him. Later at the behest of Washu Hakubi, the two travel the galaxy as archeologists exploring historical ruins. They will also have a son later as well.