Yuuhi Kurenai is an elite Jounin Ninja of the Hidden Leaf Village, she is also Team 8's squad leader, and the teacher of Shino, Hinata, and Kiba. She had a romantic relationship with Asuma, and is carrying his only child. She specializes in Genjutsu, or the illusionary Ninja art.
Relatively little is known about her, other than the fact that she graduated from the Academy at the age of 9, took the Chunin Exam and became a Chunin at the age of 13, and that she only became a Jonin soon before the start of the series.
The Anime expands on her background slightly, explaining that she had come to the village at a young age with a natural talent for Genjutsu. Because of this, the Third Hokage tasked Kurenai with helping to train Yakumo Kurama, another talented Genjutsu user who longed to be a ninja. However, because Yakumo couldn't control her illusions and thus endangered those around her, Kurenai had to seal away her ninja abilities, in turn keeping her from ever being a ninja.
Kurenai only makes a few cameos (with Asuma) before the Kurama clan arc. Yakumo resurfaces several years after Kurenai had sealed away her kekkei genkai, which ultimately proved unsuccessful. After Yakumo creates the illusion of the Hokage Residence being struck by lightning (something everyone believes to have actually happened), Kurenai takes a temporary leave from Team 8 so that she can deal with the problem. Naruto confronts her about her involvement with Yakumo, but she simply uses a genjutsu on him to keep him busy.
As she approached Yakumo's cabin, Kurenai appeared to be trapped in a rebel's genjutsu. In actuality she had attacked her attacker in a genjutsu. She discovered that these attackers were in fact Kurama clan members intent on kidnapping Yakumo. From this point, she and the opposing ninja basically fought with nothing but Demonic Illusion: Tree Bind Death, using variations on the standard theme of the jutsu. Kurenai ended up successful until the final encounter, where she was caught off guard and cut by shuriken. The blood revealed her presence to Unkai, the temporary leader of the Kurama clan, allowing him to defeat her.
Kurenai was saved by the arrival of her team, along with Naruto, Sakura, and
Might Guy. Later, when explaining to Team 8 the reasons for her departure, she claimed that the village "doesn't need any genjutsu users other than herself." This is her supposed reason for sealing Yakumo's abilities, but Shino recognized that she was lying. Yakumo, on the other hand, believed Kurenai did so in order to eventually wipe out the Kurama clan. She trapped her former sensei, Naruto, Sakura, and Team 8 in a genjutsu-created replica of the village which appeared to have been ravaged by war. Unkai was also in the illusion. Unkai, concerned by the powers Yakumo had and her continually degrading mental state as a result of being unable to control them, freed Naruto from the illusion so he could kill Yakumo. Everyone else was freed as well, except for Kurenai. Yakumo kept her trapped in the illusion in the hopes of getting revenge and answers about her past.
Naruto and the others headed back to the mountain villa and Naruto re-entered Yakumo's genjutsu world to help Kurenai. Yakumo learned that a monster named Idou that lived within her subconscious mind was the one who killed her parents. With Kurenai's help, she overcame the monster in her heart and freed Kurenai from her genjutsu. With her final mission from the Third Hokage completed, Kurenai re-assigned herself as the Jonin leader of Team 8.
Kurenai appears regularly during and following Asuma's battle with Akatsuki. After Shikamaru avenges Asuma's death by defeating Hidan, he starts taking care of Kurenai for Asuma's sake (though she has been known to insist he does not need to do so every day). He also vows to someday make the child his student. Because of her pregnancy, Team 8 has been led by other Jonin during its missions.
As the top Genjutsu specialist of the Leaf Village, most of her techniques revolve around Genjutsu. Her skill at Genjutsu is so great that it is able to enter the subconscious of a person to see one's true nature. The technique she is seen using the most is the Demonic Illusion: Tree Bind Death technique, where she makes the opponent believe that a tree has grown around them to keep them still. Once immobilized, Kurenai can appear from the tree to kill her target as she pleases, and is capable of using this jutsu multiple times in a row. She is also capable of escaping and engulfing her opponents in illusionary flower petals as well, thus proving most of her genjutsu involve flora and fauna objects.
Although we don't see a lot of Kurenai's other abilities, it is shown in the databook that she is an elite ninja and capable of defending herself. (source: First, Second, and Third Naruto Databook.)
While she has a close bond with all of her students, she is especially concerned for Hinata. Kurenai knows how Hinata is viewed by her father, even though she is technically the heiress of the clan since she is the eldest child. She is also aware of her student's infatuation for Naruto Uzumaki. When Hinata tries to offer Naruto some medicine after his fight with Kiba, Naruto is hesitant to take it. Kurenai convinces him to take it. Her personality is unyielding, honest, and simple. She also says she is a "big sister type."
It had been heavily hinted that Kurenai was romantically involved with fellow Jonin Asuma Sarutobi. The two appeared together in most of their scenes, and the other characters made it a point to note this fact on several occasions. When Kakashi Hatake found the two together at a dumpling shop, he asked if they were on a date, which made Kurenai blush. During Asuma's battle with Akatsuki members, Hidan and Kakuzu, Kurenai was often shown wondering about his progress, appearing anxious. When she learned of his death, she fell to her knees in remorse, and later laid flowers on his grave during his funeral. The truth of their relationship was made clear in Part II when Kurenai revealed that she is pregnant with Asuma's child.
most missions. She has a vest and has been seen wearing it a few times but never on a mission, once in a flashback and another in a scene with Asuma.
Kurenai means "Crimson" and Yuuhi means "Evening Sun"
Shippū! Konoha Gakuen Den! (OVA)
a short OVA
Naruto: Hidden Leaf Village Grand Sports Festival! (OVA)
Naruto: Hidden Leaf Village Grand Sports Festival! is an OVA that was aired with the first Naruto Movie.