Himura is a thirty-year-old woman with dark brown eyes and dark brown hair. While working with the NPA and the Task Force, she dresses professionally, either with a skirt or pants and with a matching blazer and a blouse.
When she defects from the Task Force and kidnaps Sayu Yagami, she dresses in a fitted white top, a short leather jacket, tight black leather pants, and black heeled boots.
Himura's personality is never truly revealed, as she's rarely seen outside of an undercover agent persona. Nonetheless, she is a determined and capable agent whom L trusts. She works efficiently and is willing to break the law for L, Near, and Mello, and even kidnaps and traumatizes a teenage girl to help stop Kira. She is able to keep her emotions in control even in highly stressful situations, such as when making the notebook trade at gunpoint and when she is personally concerned for L's safety.
Himura is very quiet and reserved while working with the police and the Task Force. Without protest, she follows orders of questionable morality and legality, such as spying on the Yagami family. She takes instruction and does her job efficiently. As her job is to infiltrate the task force and observe, her demure personality in this setting is possibly not a reflection of her actual personality.
After it comes out that she seems to be behind Sayu's kidnapping, she is more direct and confrontational. However, this is also part of an undercover act; she's pretending to be a mercenary after the Death Note for selfish reasons, but she's actually still working with Near/Mello to catch Kira. Nonetheless, she acts ruthlessly while under the act, likely traumatizing Sayu, showing no remorse as Sayu is bound and crying before her, and holding guns to the heads of the Task Force members with whom she had previously worked.
Himura was an FBI agent before the start of the series. L and Himura have worked together in the past and he trusts her, which is why he brings her into the Kira case.
Himura is undercover for most of the series with the NPA and the Task Force. With the NPA, she's with the 2nd Criminal Investigation Support Division.
Himura joins the Task Force under Soichiro Yagami along the other members. After L set her up as an NPA agent, she brings the online Kira discussion to Soichiro's attention and requests to be added to the Kira investigation. After joining the Task Force, she works quietly in the background, mostly doing computer and technological work. The alias she is given as part of the Task Force is Taeko Makimura (牧村妙子, Makimura Taeko).
After L's death when Near has taken over the investigation, she apparently defects and kidnaps Sayu Yagami to trade for the Death Note. It comes out to the Task Force that Himura was not really with the NPA, and she was planning all along to get Kira's weapon. But this is in fact part of Near/Mello's scheme to corner Light Yagami, Misa Amane, and Teru Mikami into revealing they are Kira. She successfully gets the Death Note in a trade for Sayu and gets away. Near also defects the Task Force under their Mello personality, and they work together outside the Task Force to catch Kira.
Light gets Himura's real name and controls her with the Death Note. He first has her bring the Death Note she'd taken from the Task Force to Light. She then kills herself in a suicide explosion in an attempt to also kill Near/Mello. However, Near/Mello escapes the explosion.
- Himura's real name is Halle Lidner, and she works with both Near and Mello as the original Lidner does.
- Similar to Naomi Misora, Himura worked with L prior to the series on previous cases and she used to be a member of the FBI. She dies by suicide after Light writes her name in the Death Note.
- Himura takes on some of Mello's characteristics when she kidnaps Sayu, and her black leather clothing resembles Mello's during this arc.