Asai is over average height with a short stylish bob hairstyle, which is depicted in dark brown with pale skin, and slate mixed with blue eye color. Her outfit resembles a military officer outfit as it is depicted in sky blue. The very top of the collar is white, making the jacket itself to have a white outline, along with multiple of buttons coming down in the middle of the jacket; leaving a small split hanging. Her shoulder blades on the outfit is yellow as what it appears to be suspenders which descends down towards her blue belt, along with a silver buckle. She also has yellow and white designs on the bottom of her jacket sleeves. She wears white gloves and white heel boots. She holds her bust area with several layers of bandages underneath her outfit, disguising her image. She wields two katanas on the left side of her hip.
As she was a child, she had on a sky blue kimono with a pink belt wrapped around her abdomen, making it tie in a ribbon bow style in the back with flip-flops.
Although being described as vicious, due to her debut, overall, Asai is a respectful and helpful person. She also shows her gratitude to Otomi after she gave her food, due to her not eating in three days since she ran out of money. She depicted her rudeness towards Keiichiro, believing he was responsible for her father's death as Otomi mentioned to her that she quickly jumps into conclusions. Asai also shows more respect and admits, making her very honest when she's in the wrong as she repeats her apology towards Keiichiro after mistaken him to be her father's killer, thinking that whoever had the Tokugawa seal was responsible. She can also be described as a strict and straightforward person.
Throughout her life, Asai lived with her father as the both of them were very close. Six months prior to the main story, he was killed by an unknown person as she began searching for his killer. Although, it was very difficult for her to
travel alone, including for her to get through border checkpoints, and being chased by lustful men she was determined to avenge her father.
After catching Keiichiro attempting to grab a woman's breasts, Asai grabs him by the arm and throws him in the air. When she explains to Keiichiro on how he's treating women and calling him less than a man, Hyakusuke tells Keiichiro that Asai is a woman and not a man, which causes Keiichiro to freak out. This made Asai unsheathe her katana to get into a quick battle with Keiichiro when Otomi comes from the roof top and throws down her stick at them, nearly hitting Asai's toe. While Hyakusuke calls her out, Otomi teleport to come down to them as both Keiichiro and Hyakusuke bolts off. This made Asai faint as Otomi sets her attention to the young woman.
A little later, Asai thanks Otomi for feeding her food as Otomi replies that we all supposed to help each other out. In return, Asai brought up that she don't mind giving Otomi a hand with anything. As Otomi puts Asai up to lend a hand at the bathhouse, she doesn't expect for Otomi to force her out of her clothing and make her put on the women bathhouse uniform. While Asai greets everyone with a nervous expression on her face, Keiichiro instantly ignored what Kiriko was speaking of and set his sights on Asai. As Keiichiro went to her and try to ask her out on a date, Asai snapped at him; calling him a bastard and almost landed a quick punch to the face when Otomi interfered; blocking Asai's hit. Keiichiro asked Otomi about Asai; not recognizing her in the bathhouse uniform clothes and a wig, which Asai had on, along with Hyakusuke, in which he asks as well about her wearing the bathhouse uniform. Asai wondered to herself that both Keiichiro and Hyakusuke doesn't recognize her. In return, Otomi introduces Keiichiro to her as she puts Asai to work with Keiichiro, which Otomi responded in a punishment that Keiichiro has to deal with.
In the meanwhile, Keiichiro gathers everyone together at the bathhouse to make a introduction for Hyougo as the new bathhouse worker, along with other things. When the men gives her compliments, she blushes; being embarrassed as she asks Hyakusuke about what's going on. He explains to her what Keiichiro was doing, leaving Asai repeating what Hyakusuke said. After the speech, the two instantly got to work to help out around the bathhouse when Keiichiro asks her if she was okay, saying to her to take her time. He is then seen helping a elderly while Asai was by his side. Afterwards, she is then seen with Otomi when Otomi asks her about her day at the baths, which Asai answered her about it being rough. The two spoke more when Otomi tells Asai about Keiichiro not being tired when a young girl asks Keiichiro to play with her. As the two watched Keiichiro play with the little girl, Otomi explains to Asai that how Keiichiro is the face of our baths, since he places a smile on everyone's faces.
When Asai listened to Otomi and watched Keiichiro, she reminisced her father done the same playing technique that Keiichiro used on the little girl: swinging and she whispered out, Father. As both Keiichiro and Hyakusuke opened the door the room where Asai was in, Keiichiro said to her that they were done for the day, as Hyakusuke responded something to Keiichiro when he spotted Asai and said something to her. Asai then made a angry facial expression, which startled Keiichiro and quickly got on her knees to give him an apology about her actions.
Keiichiro Tokugawa- At first, she doubted him, stating that he was less than a man, calling him weak due to him grabbing on women and thinking that he killed her father. She completely misjudged him and realized how much he got along with the customers at the bath house, and including him saving her twice: when the part of the bath house building collapses as he pushed her out the way and after Susanoo almost crushed her. She constantly apologizes, making her take heed to him reminding her of her late father.
Otomi- Asai thanked Otomi for giving her food after not eating for three days due to haunting down her father's killer. In returned, Asai didn't mind of doing Otomi a favor until Asai had no choice but to work at the bath house, alongside Keiichiro.
Chiharu and Kiriko Hattori- Asai seems to get along with both ladies who have a crush on Keiichiro. Chiharu helped Asai to wear the kimono again when she helped herself to rip off her medical bandages as both Chiharu and Kiriko were shocked to see not only Asai's bosoms were bigger than the both of theirs, but Asai revealed to them that she's a virgin, just like them.
Hyakusuke- Both Asai and Hyakusuke developed a mutual respect for one another.
Souji Okita- A member of the Shinsengumi, these two ladies has a bit of rivalry after Souji and her crew, the Shinsengumi tries to attack Keiichiro and Kiriko as Asai takes her head on.
Expert Swordswoman: Asai is a excellent swordswoman as she gave Keiichiro a run for his money. She is also very quick with her katanas as well; making her very skillful in battle. However when she went against Souji, the tables were turned and Souji gave her a run for her money.