Misaki Masaki Jurai (柾木 美砂樹 樹雷, Masaki Misaki Jurai) is empress of the planet Jurai.
Misaki is the second of Emperor Azusa Masaki Jurai's two wives, and the mother of Ayeka and Sasami. Misaki and Azusa's marriage was arranged by her mother, Seto Kamiki Jurai, also known as the "Devil Princess of Jurai." Misaki was born into House Kamiki of the Imperial Family, being the daughter of Lady Seto and the Head of the House, Utsutsumi. Misaki is also the adoptive sister of Noike and the grand daughter of Ranma and Nabiki Kuramitsu. She possesses immense physical strength, incredible skill in Infinity School Martial Arts, and is the Supreme Commander of Jurai's Royal Bodyguards.
Misaki is extremely close with Azusa's first wife, Funaho, and refers to her as Oneesama ("big sister"), or "sis." When Funaho was first brought from Earth to Jurai by Azusa, she was a stranger in a strange world until she met a young Misaki and the two became fast friends. Misaki is bonded to the Royal Tree Karin, and Funaho bonded to Mizuho. The trees being twins, both ships have the ability to join together. The relationship being a parallel to Funaho and Misaki, considering each other sisters married to the same husband.
With Misaki and Azusa's relationship being one more similar to that of a big brother/younger sister than a romantic one, once upon a time, Misaki had certain feelings for Azusa and Funaho's son, Prince Yosho. Misaki would visit Yosho's room every morning in the Royal Palace, resulting in Yosho falling in love with her. However, the brief attraction ceased once Misaki and Funaho arranged for Yosho and Ayeka to be betrothed. Misaki certainly had some feelings for Yosho, but possibly would not have acted on them. Regardless, once Seto learned of Misaki's frequent visits to Yosho and the potential for scandalous behavior to happen, Yosho was sent to Galaxy Academy and Misaki was forbidden from being so friendly.
Misaki is known for having her two daughters address her in a certain way, and is exceedingly overprotective of them; when she visited earth Ayeka cried out to Misaki, calling her "Okaa-sama!" in a high-pitched voice. Ryoko thought this was hilarious, but her laughter would be met by an angered Misaki cruelly and brutally stretching Ryoko's face. This sadly could have been avoided, as Ayeka warned Ryoko against saying anything. A fight was only avoided by Ryoko reading from a sign that Sasami had written: "I'm sorry, pretty young lady." This was also why Ryoko terrified to answer the door when she thought that Misaki had returned, when in fact it was Tennyo Masaki.
Misaki is very smothering and likes hugging and coddling even those she doesn't know. Upon arriving to Tenchi Masaki's home on Earth, she pretended that she thought Ryoko was a grown-up Sasami and proceeded to hug her with crushing force -- and upon seeing the real Sasami, Misaki gave a pause before simply throwing Ryoko against the wall to get to her daughter.
It is revealed that Misaki will become -- and perhaps already is, to some extent -- the "Counter-Actor" (Kauntaa Akutaa), the sentient sum total counter-force to all of the Choushin's actions. From what has been seen of the counter-actor, Misaki has the ability to cause harm to the Choushin -- Washu, Tsunami, and Tokimi, the three goddesses who created all of existence-- with an immense rage over their meddling. There has to be a counterbalance; for every action, there must be an equal and opposite reaction.
Misaki becomes the Counter-Actor thousands of years into the future on Jurai when both Azusa and Funaho have died, causing her to go mad. Z, a man capable of generating Light Hawk Wings like Tenchi, went into the future to bring the Counter-Actor to do battle with the Choushin.
When counter-actor Misaki attacked, nearly strangling Tokimi's lower-dimensional shadow, and viciously striking Tsunami when she tried to reason with her, Tenchi appeared in a glowing form to calm her down. The two of them kissed and disappeared from view. Ranma has now started taking steps to avoid this outcome.
Her appearance does not fundamentally change, but she becomes clad in some kind of black and red quasi-matter that distantly resembles a dress and long gloves -- Misaki could not endure the pressure of the energy that was for various reasons contained within her, so she ended up going on a rampage through Jurai. To put a stop to it, Juraian fighters at first didn't want to wound her mortally so they just shot at her limbs. Since she was completely unperturbed by that and refused to stop, the Emperor of Jurai at that time finally had enough and issued the order to eliminate her. So they struck and shot at places like her heart, head, and neck, resulting in her appearance. Additionally, her face grows almost unrecognizable from how her rage distorts it.
The full capabilities of the counter-actor haven't been explained, but it seems that she can negate some of the abilities of other beings. Most noticeably, the presumably omniscient Choushin seemed unable to notice her proximity to Tokimi, and the normally unequalled power of the three Goddesses could do nothing to stop her in the third dimension without completely destroying it.
This could also explain how Misaki was able to harm Ryoko both unintentionally (with her hug) as well as intentionally (when she started tugging on her face). It would be assumed that Ryoko couldn't be hurt by these actions, but Misaki's abilities as the counter-actor -- even if not fully awakened -- may be the reason for this.