Tokimi is one of three beings known as Chousin - higher-level dimensional beings, the other two are her sisters Tsunami and Washu. All three sisters had wrestled for countless millennia over one question - was it possible that a being more powerful than themselves can be created. While Tsunami and Washu took separate paths to find out that question, Tokimi had remained in the Chousin's home dimension. With the assistance of the guardians of other dimensions, D3 being one of them, she manipulated random subspace fields to find out if doing that was possible. She had also enlisted others in her quest, like Dr. Clay.
One of those manipulations had produced promising results: during a space battle, the being known as Z had gained immense power, which included the Lighthawk wings. In order to study him more closely, Tokimi had taken Z as her servant. However, she had found that Z was erratic and hot-headed; most likely he would destroy the universe is left unchecked. So she continued her quest until a message from Dr. Clay had led her back to her departed sisters... and someone they were watching, someone else who also had the power of the Lighthawk wings - Tenchi Masaki.
Intrigued, she ordered Z to observe Tenchi but not to interfere. Z, however, saw Tenchi as a threat to him, and initiated steps to have the boy killed, but made it appear to look like someone else had did it. He had altered a message Mihoshi had sent to her family, which her grandfather Minami had sent her brother Misao to kill Tenchi. But when that plan failed, Z took matters into his own hands, the end results having Earth nearly destroyed and Z fighting Tenchi near Saturn.
It was just as Z was about to strike a fatal blow when Tokimi finally intervened. However, Z was also prepared. He had enlisted the aid of a being known as 'The Counter-Actor', which had two forms - a red ring which had surrounded Tenchi, preventing Tokimi from offering aid to him. Later, when the rest of the Chousin sisters were called upon to contain Tenchi's out-of-control energies, the Counter-Actor took a different form - a demonic version of Empress Misaki, and in this form, the Counter-Actor strangled Tokimi. However, Tenchi was able to regain control of his power and calmed the Counter-Actor before Tokimi was killed.
Later, when Misao and Minami Kuramitsu and Mashisu were called by Mikami Kuramitsu for their part in trying to kill Tenchi that Tokimi showed another form... that of a small child. Tokimi had to leave in order to set right abnormalities in the universe, but returned to the Masaki home just in time for the wedding of Nobuyuki and Rea Masaki.
Tokimi also used her powers when it was discovered that some of Noike's cells were tampered with... they all had the logo of Dr. Clay on them. The source of this was that within Noike was the little girl that had haunted her dreams. Tokimi had removed the girl from Noike and Washu removed Dr. Clay's tampering. It also turned out that the little girl was actually the discarded female half of Kagato. After it was done, Tokimi returned her to Noike.
It is uncertain if Tokimi will remain with the Masaki clan.
(source: Absolute Anime)
