Complete Monster: Shao-Li, a assassin for the Triads, is infamous for her poisonous methods and remorseless attitude towards her kills, receiving the nickname "The Cold-Blooded Killer". Introduced after one of her assassinations, Shao-Li is called by her forces to help deal with the duo assassin Noir and the Soldats due to their presence in Hong Kong. Tracking them down by using an informant, she leads a charge to kill the two hired killers and eliminate the informant, since he's no longer of any use to them. When Noir was able to fight off the attackers, she retreats and returns to his employers only to kill them off herself so she could realign with the Soldats and save herself. Approaching them, she was immediately rejected due to her history of backstabbing, and in retaliation Shao-Li tries to kill their representative. Even to the ruthless and unscrupulous Soldats, Shao-Li was seen as nothing more but a deadly poison for anyone and everyone.
Evil Is Cool: Chloe, the third Noir. She is just as deadly, if not even more, as the other two. Instead of guns, Chloe weapons of choice are her little throwing daggers, and she effortlessly kills gun-wielding enemies with them. During her introduction, she has Mireille at knife-point while Kirika has Chloe at gunpoint, and Chloe confidently says: "Let's see which one of us is faster."
Though Mireille's brother is never named on-screen, there's a tendency to name him "Roland" in some fan works, which actually comes from a mistranslation of their father Laurent's name, which in Japanese winds up sounding like "Rorando", which is identical to the pronunciation of Roland in the same language.
Also, the idea that Kirika is a Self-Made Orphan and killed her biological parents and/or the couple who was posing as her parents prior to the first episode is pretty commonly accepted even though it's never explicitly stated in the series itself.
Much of Kirika and Mireille's prominent actions can be interpreted as such: ( Mireille not being able to kill Kirika after their "contract" was up as promised, even after finding out Kirika was the one to kill her family, Mireille killing her only remaining family member for Kirika's sake - the one who raised her after the demise of her parents, and the letter Kirika left for Mireille can very much be seen as a love letter.)
Said letter even has Kirika addressing Mireille as "My dear Mireille." The word in the original Japanese that Kirika used for that? Daisuki. This indicates that Mireille is someone Kirika cherishes very much.
In addition to the Les Yay between Kirika and Mireille, there are also significantly less subtle examples between Kirika and Chloe and Mireille and Lady Silvana.
Magnificent Bastard: Mistress Altena is a high priestess within Les Soldats who seeks to cleanse both the organization and the world of corruption. Driven by her childhood trauma of having her village destroyed by soldiers, one of whom raped her, Altena raises Chloe as her surrogate daughter with genuine love and sends her to watch over the titular Noir duo, Mirielle Bouquet and Kirika Yuumura, while sending waves of assassins after them to train Kirika and make her stronger. Using Chloe to manipulate the Noir duo, Altena deceives them into eliminating all her rivals, eventually unveiling her true plan to have Chloe kill Mirielle so that Chloe and Kirika can become the True Noir. When Chloe is defeated and killed instead, Altena makes one final stand against Mirielle and Kirika, and when defeated, dies on her own terms, throwing herself into a lava pit. Ruthless yet affable, Altena never loses her chillingly stoic demeanor, even in death.
Narm: Altena's scene in front of the volcanic vent with her hair and skirt blowing around made more fans laugh than think it to be dramatic as intended and spawned comments of "Octopus!" and parody fan art of her imitating Marilyn Monroe.
No Yay: Lady Silvana, aka the Intoccabile, gives Mireille an excessively long (and open-mouthed) Kiss of Death. And beforehand, when they were children, she was veryobsessed with Mireille, traumatizing her for life. It's also implied that she has a general obsession with domination and control, and used the kiss to put fear into Mireille by confusing her and establishing dominance.
The Woobie: Kirika practically holds up a sign that says "Please Hug Me!!" whenever she is crying. Chloe also gets in on the Woobiedom in the final arc, and even somewhat before that.
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