I’m sorry I took long to answer, I swear I couldn’t stop thinking about it.
If you put yourself in a third person view, you can easily see why Halle isn’t written in a sexist way (according to manga standards in 2000’s anyway. Of course we’d, as reader, expect a lot more of character development if DN was a book written nowadays).
**The shower scene
Some people complained that showing Halle’s showering wasn’t necessary. Truth be told, maybe the fact DN was published in Shônen Jump isn’t unconnected with the shower scene. However, other readings are possible.
There is a common misconception that showing a woman’s body is inherently sexist. It’s not. It depends mostly on the author’s intent behind the scene.
If you look closely at this scene, what do you see ? Halle is pretending to act normally because she doesn’t want Near to suspect something is going on. Her behavior isn’t irrational. She needs to talk to Mello and the bathroom is unmonitored. Her first reaction is quick and clever.
Then she bathes in front of Mello.
In eastern cultures, bathing can have a strong spiritual symbolism of cleansing and purification. An interesting parallel can be made with Mello’s death (Fire is also a purification. Paul speaks of the second coming of the Christ as a “blazing fire”. On a side note, according to Japanese philosophy - see the Book of Five Rings- fire is an unpredictable force. Very much like Mello. So Fire, though destructive, is not necessarily negative on a symbolic level). The act of bathing may be read in another way than mere fanservice (especially since we don’t get to see much of her body).
Plus, contrary to most shônen mangas (remember DN isn’t classified as a seinen for reasons I don’t get) Mello’s reaction to Halle’s nudeness isn’t comical. He’s isn’t seen screaming dramatically or nose bleeding. Nope, he remains respectful and professional, business focused.
Last but least, Halle feels comfortable enough with Mello to shower in front of him. Halle is THE character who will convinced Mello to really work hand in hand with Near. She is the one who talked Mello into reason when he was going to shoot Near (maybe he wouldn’t have done it but well). Of course they have a bond. This shower scene only highlight how close they are. She’s even mocking him (“will you sleep in my bathroom?”) when he’s threatening him.
** The Warehouse
Halle is also one of the few characters to speak during the Warehouse scene. It could have been a tête-à-tête with Light (Kira), Mikami (who is a metaphor for people who believed Kira is Justice and genuinely worked for him), Near (L’s avenger = “I will humilate Kira”) and Matsuda (the “good” son).
But Halle is talking when Mello is mentioned. Gevanni and Near talk alternatively to explain how Near did trick Light. He’s on an equal footing with Near in the sense they both equally contribute to the explanation. But at one point, Halle steps forward and speak in front of her very much surprised collegues to explain Mello’s actions (x). She’s far from being absent in this scene. She isn’t just “the woman in Near’s team”. She’s Mello’s friend.
When Near’s voice shivers when he’s talking about Mello’s death, she has her own panel when Gevanni and Lester share one (x).
It might seem like it’s details but it’s the scenarist and illustrator’s work to care about details.
** Near and Mello’s meeting
Not much to say. She is the one to stop Mello from shooting him using very much logical arguments (notice how the men all react in an emotional way, Mello and Near included. She kept a cool head).
** Halle and Misa / Takada’s meeting
Let’s just remind everyone that Halle is putting her life in danger by spying Takada. It’s not a petty task, Near even says it himself (x). By the way, have you noticed the scene that follows the restaurant scene is Gevanni spying on Mikami ? Ohba’s message is quite clear : their role is equal within Near’s team and I never understood people who thought the contrary.
Halle’s maturity is peculiarly blatant when you compare her to Misa and Takada. Misa is living in a lie, drinking a lot, obviously unhappy. Takada is bragging and came only to humiliate her.
And yet, when the narrator could have easily made Halle think “those women are so futile”, she doesn’t judge them. I believe Halle does have an opinion about the events of that night however she remains perfectly professional. She’s fully playing her CIA agent duty, quietly observing and then analyzing the meeting between two important suspects. It is textually highlighted by the numerous “……” (x)(x)(x)
And then she does her report to Near and this scene is tremendously important to understand Near. He DOESN’T MOCK Takada and Misa. He calls them “enslaved” because they both don’t realize they are being lied to by the man who defeated L himself, lied to his whole team and family. Near states a fact and tells Lester he doesn’t find the whole situation “funny”. He’s far from engaging in any kind of victim blaming (even though they’re murderers - I don’t reduce their responsibility- they ARE manipulated and lied to, abused or killed).
TL; DR : Halle isn’t shown acting in a sexist way. And apparently the authors didn’t depict her in a sexist manner unless I am missing something. Hence my claim there’s nothing sexist about her character.
=> For Mello
I urge you to read this :) (x)
Hope my answer is satisfying !!! If I’m unclear or anything do tell.