In the final episode of the third OVA, it was revealed that Kagato was actually a hermaphrodite, having long discarded the female half out of spite for the gender. That gentler female half had resided within Noike Jurai, whereas Dr. Clay had placed a seal on the girl, preventing the female Kagato from completely merge with Noike. This had allowed Z to spy on the family through Noike's eyes while he plotted to kill Tenchi.
During the battle with Z, Tenchi was cut in half when he went to save Ryoko from a similar fate. It was during the brief instant in-between that Tenchi was able to meet the girl Kagato, who was found crying during a battle. Tenchi was able to comfort the girl, telling her everything was alright. Girl Kagato then asked if she could stay with him forever, which he agreed. But before Tenchi could inquire about something she said (during the battle, she pleaded, obviously to her male half that she was a Kagato too), he was drawn back into the battle with Z, with the girl pleading him not to leave her.
After Washu had noted that, before Z's attack that she knew that he was spying on them through Noike, it was found out that the Kagato cells were in her (the cells had Clay's logo on them), Tokimi used her powers to remove the female Kagato from Noike. Soon, Washu was able to remove the seal, and the female Kagato soon fully merged with Noike.
