Audience-Alienating Premise: It is a bloody, lurid series about a girl kidnapped by a Hong Kong gang leader to be his Sex Slave and becomes horribly broken. It's also a smutty shoujo romance. Viz Media reportedly dropped its license of it for this very reason. In fact, most of Mayu Shinjo's works are this. It's the main reason only a small chunk of her works have ever been translated and/or licensed.
Big-Lipped Alligator Moment: One of the assassins attempted to kill Hakuron by sniping...with an Assault Rifle being wielded like a bazooka...and a targeting hud suddenly appeared out of nowhere on his POV.
Designated Hero: Uon Hakuron, a possessive boyfriend who has Kurumi kidnapped and forces himself upon her a number of times, and yet is treated as the hero of the story.
Mayu-tan's Kung Fu: This page◊ in which Hakuron shows off his martial arts skills to Kurumi has spawned a ton of parody fanart on Pixiv.
The Best Assassin in the World explaination Written as (世界一腕の立つ殺し屋, Seaki Ichi Ude no Tatsu Koroshiya), this is a nickname given to an assassin with no name who was hired to kill Hakuron, His nickname comes from a client's order for "the best assassin [they] can get!". He became famous for his scenes in chapter 11 and 12, where he attempted to shoot Hakuron in a park. The reason why he also became a laughingstock is his unorthodox style of sniping Haku down.
Narm: People have laughed their butts off after merely reading plot summaries about this series. Um, yeah.
Special mention goes to the scene where Kurumi donates blood to Hakuron to save his life, and when he wakes up and finds out, he bites open the skin on his wrist and starts licking up his blood, because even though they can't be a couple in real life, at least they can be together inside his bloodstream.
Aside of Shinjou's rapes? Considering that Haou Airen is Darker and Edgier compared to other mangas of hers, the amount of violent scenes can get very high.
Also, no matter what you think of this manga, there is a scene that fits here perfectly: Reilan's bloody death at the end of Hakuron's pistol. The Gory Discretion Shots and their aversions were very well paced and made the scene genuinely terrifying.
So Bad, It's Good: It's actually so cheesy, over-the-top and ridiculously overblown, that some people specifically read it to have a laugh. Oops?
Tear Jerker: During the short Story Arc that involves Kurumi running away and coming across Kaafai and his family, Kaafai’s mother turn a serious 180 towards the former when Kaafai unsuccessfully attempts to rescue Kurumi from Hakuron’s hands and gets beaten by Hakuron’s men. Kaafai’s mother was going from a Shipper on Deck for Kurumi/Kaafai into hating the poor girl for getting her son beaten by the mafia. Before that, Kaafai’s mother didn’t Kurumi’s a bad kid - now she didn’t seem to have any desires to ever see Kurumi, again...
Too Cool to Live: Hakuron was considered The Ace and the most feared leader of the Black Dragon Gang, yet he was gunned down by the boy who was challenged to take Kurumi away from the former - all on the day of Hakuron’s wedding.
The Woobie: Huo Long, the most sympathetic of Hakuron's group.
Kurumi. Holy crap, Kurumi. Maybe one of the biggest woobies EVER created by Shinjou, no matter whether she intended it or not... That poor girl really needs hugs.
Unintentionally Unsympathetic: For many, Hakuron is such terrible and abusive boyfriend that they were satisfied when he got killed, almost karmically, and the girl he messed up so badly regained her normal life.
◊ in which Hakuron shows off his martial arts skills to Kurumi has spawned a ton of parody fanart on Pixiv.
