Kaoru Shiratori (白鳥 かおる Shiratori Kaoru) was Kisara Nanjō's principal lieutenant who joined Shinpaku when she did where she is known for her long blond hair. She is a skilled practitioner of Tae Kwon Do, but since she was ranked the same as Shinnosuke Tsuji was under Kisara during the Ragnarök arc, it is assumed that Shiratori was as just as strong as he was at that time.
Shiratori is actually a tall young woman with distinctively slightly wavy waist-length blonde hair that has has a few hair strands hanging over her face, light purple eyes and a lean build.
She is typically seen wearing a white button-up shirt, dark pants, and a long blue coat that reaches down to just above her ankles. Due to her refined appearance and long hair, the lower-ranking members of the Shinpaku Alliance, not realizing Shiratori actually is a girl, initially insulted her feminine appearance, creating a tension in the air during the party they held to get to know each other. She is revealed to be a girl after she fought Kōzō Ukita. The members of the The Valkyries seem to have known that she was a girl from the start.
Shiratori is typically a very calm and reserved individual who rarely ever speaking unless directly addressed. She also seems to be self-conscious about her physical appearance and is usually seen dressed in fine clothing, even while she was a member of the street gang Ragnarök, and has been shown lashing out at people for pointing out her somewhat feminine appearance.
Shiratori displays a tremendous amount of respect for her superiors, particularly Kisara Nanjō, and will to do whatever she asks. This devotion to her extends beyond her team affiliation, as she was quick to follow her lead and join the Shinpaku Alliance, even working to get along with the group's lower-ranking members despite her noticeable dislike of them during their first meeting. She possesses a strong desire to be strong like Kisara and protect her, a goal which prompted her to take up Tae Kwon Do as her primary martial art.
When several of the Shinpaku captains plan a double date, Shiratori decides to attend despite the fact that Kisara has already agreed to go with Ukita, prompting Miu Fūrinji to suggest a love triangle. This is later proved true during the date when Shiratori continually competes with Ukita for her attention.
Due to her appearance, several males mistook her as a man due to her boyish facial features till she decided to swim at a pool revealing she's a woman and just has a lean figure. This appears to be a running gag on her part (albeit indirectly) such as when she was at the amusement park with the others, Ukita believed he saw her "doppelgänger" who looked just like "him" but as a woman, much to her embarrassment. Also, due to Ukita proving himself in his fight with her, Shiratori has now developed an affection towards him, going as far as to bashfully ask Takeda about what Ukita likes. She even tried to get his reaction to see her as a woman, but due to his oblivious nature, she kicked him in the face for believing her to be a male still.
Shiratori is first seen early on the series standing among several Ragnarök members when Tsukuba appears at Kisara's headquarters to receive orders. She continues to make several cameo appearances whenever her superior is shown issuing commands from their hideout, and takes the field when the Ragnarök Division mobilizes to punish Ikki Takeda for his treachery. After Kisara is defeated by Miu in the following battle, she catches her in her arms and retreats alongside her fellow delinquents. She later joins her group of lackeys in an attempt to ruin Miu's play of Romeo and Juliet, but Kenichi Shirahama easily defeats the thugs. This prompts Shiratori to personally fight him, but her superior prevents her from stepping up and decides to handle the situation herself. After a brief skirmish where he refuses to fight back, Kisara grows tired of the farce and leaves alongside Shiratori.
Following Kisara's resignation from Ragnarök, she stays by her side. She is present when Haruo Niijima tries to blackmail her into joining the Shinpaku Alliance, and offers to attack the alien boy before frantically helping Kisara in her feeble attempt to collect the blackmail evidence. She joins them alongside Kisara and agrees to attend a party to make friends with the Shinpaku grunts. During the gathering, Matsui pokes fun at her hair, only worsening the tension in the room. Taichi Koga laughs along with the others, prompting Shiratori to punch him in the face. Although the majority of the Shinpaku members are attacked by Berserker and subsequently put out of commission, they recover and appear during Kenichi's battle with Odin. Shiratori joins them wearing an eye-patch due to her injuries, and they quickly work together to fight off Ragnarök's remaining forces.
She is later seen accompanying the Shinpaku to the D of D tournament, but did not participate in the fighting. Although she wanted to participate in the upcoming fight against Shō Kanō, Nijima deemed the Yomi leader to be too dangerous an opponent and forfeited the match to protect his remaining teammates. Shiratori attends several Shinpaku meetings at Kisara's old hideout, which had been converted by the alliance into their new headquarters.
She appears much later on when Takeda and Freya agree to go on a double date with Kisara and Ukita, apparently having volunteered to accompany Kisara for unspecified reasons. During the group outing, Shiratori continually tries to show off in front of Kisara while tending to her every need, making Ukita jealous. When the group encounters a gang of thugs attacking James Shiba, they inadvertently get involved in the ensuing battle. Ukita panics and attempts to protect Kisara from the armed delinquents, but Shiratori jumps in and quickly takes out their attacker with a kick. She demonstrates her skills in Tae Kwon Do by helping the others fend off their remaining enemies, loudly declaring that her goal in life is to be like Kisara and protect her from danger.
The next day Shiratori turns up at Kōryō High School and gets into an argument with Ukita over Kisara. The two agree to fight in order to determine who deserves Kisara's affection, the heated argument attracting attention from several bystanders. Kisara blushes in embarrassment and tries to break up the fight, but ultimately leaves the scene when her efforts prove wasted. The next day Keichi, Miu, and Kisara show up to watch the fight. She urges them not to hurt each other too badly. Shiratori easily beats him and then an assassin arrives and when Kisara tries to fight him, Ukita rises up and grabs him and they fall off the ledge. They both survive thanks to Shiba's interference and are taken to Akisame to heal and Shiratori takes the blame for Ukita's kick injuries. Later, she and the other females and Takeda go to a pool and states it's her loss and agrees with Takeda's statements about Ukita being a good man and seems to be jealous of Kisara now. When she takes off her jacket, she reveals, much to Takeda's shock that Shiratori is a woman. Shiratori is flustered that he didn't know and then bashfully asks him about what Ukita likes and Takeda realizes she's developed a crush on him.
Following the discovery of a Yami base, Shiratori and the rest of the alliance travel to the location but are forced to stay by the masters. However, after they leave, a limo that took the YOMI members from before arrive and Berserker and a member named Lugh come out and prepare to fight them. She watches as Takeda fights against Lugh and becomes shocked to see Ukita try to save Takeda from sacrificing his left arm, but is saved by Kenichi. Lugh leaves, but promises Takeda that he'll crush him first next time they meet.
She later attends the amusement park with the other Alliance members and tries to get Ukita to notice her only for him to walk right by her, much to her shock. She talks with Takeda believing she was unappealing in her bathing suit and starts covering herself with her jacket not wanting to be seen in a bathing suit again. As Takeda tries to help her get Ukita to notice her, Ukita says he's been looking for her and that he saw her "doppelgänger" and that she looked just like "him" but as a woman and should be careful to see her again, which results in an embarrassed Shiratori to kick him in the face while Takeda runs laughing hysterically. At night, she walks with Kisara wondering where Ukita went and that everyone has left the park and while Kisara thinks that's lucky for them Chikage appears in front of them.
The two fight Chikage, however, Shiratori is no match and is easily defeated prompting Chikage to say that small fries should stay out of it. Eventually, after Ukita shows up and takes a massive beating, Shiratori and Kisara beg Chikage to stop or he'll die. Luckily, Chikage regains her senses and cries uncontrollably over realizing what she did. Mikumo shows up and takes her away with the intent to control her completely as Shiratori takes Kisara with her away from the flames approaching.
In the Epilogue, Shiratori works along side Raichi Li in Niijima's business in the Shinpaku Alliance.
As a former senior member of Ragnarök, Shiratori was ranked as a fairly capable fighter, although her skills pale in comparison to the captains of the Shinpaku Alliance. Like Kisara, she specializes in the same style of Tae Kwon Do, and hopes to be like her one day. Despite, the fact she has rarely been shown in battle, she is strong enough to take on armed thugs with her bare hands, as shown when she protected Kisara during a group outing with several of their fellow Shinpaku members. She claims that in terms of raw power, Shiratori's kicks are even stronger than her own. After accepting a challenge from Ukita, she effortlessly destroys the Shinpaku Captain in a display that impresses even Miu. Kisara goes on to explain that the only reason Shiratori did not strive to become one of the Eight Fists in Ragnarök was because she lacked the interest.
- vs. Kōzō Ukita (Win)
- With Shinpaku Grunts vs. Berserker (Lose)
- With Shinpaku Grunts vs. Ragnarök Thugs (Win)
- With Takeda and Freya vs. 3 Gang Members (Win)
- With Kisara vs Chikage Kushinada (interrupted by Mikumo Kushinada)
- Kaoru's surname Shiratori means "white" (白) (shira) and "bird" (鳥) (tori).
- Shiratori is one of three girls that has fallen in love with Kōzō Ukita with the other two are Kisara Nanjō and Kaname Kugatachi.
- A running gag is that Shiratori was constantly mistaken for a boy (although the Valkyries seemed to be aware of her true gender). The confusion is not limited to the other characters, but the staff responsible for the English dub has mistakenly given her a male voice in the English version.