Awesome Music: "Renegade", the opening has gotten a lot of deserved love for its style and general awesomeness.
Complete Monster: The vicious mobster Ivan Glaziev is the man who leads the purge of the persecuted Twilights- those who have enhanced abilities, handicaps and shortened lifespans thanks to the Fantastic Drug Celebre. Glaziev is seen having Twilights butchered, tortured and killed with his attacks not sparing innocent civilians or even children. One Twilight is blackmailed into attacking one of the only safe havens for the Twilights by Glaziev holding his wife and daughter hostage. When the man is dying, Glaziev cheerfully informs him that he had already killed the two by chopping their limbs off and throwing them away. Possibly Glaziev's worst act is keeping the Twilight Erika as his personal hitwoman, having conditioned her with years of mental and sexual abuse. When he reveals this to Erika's long-lost brother Delico, Glaziev says it gave him a genuine thrill to rape her every evening, knowing she had the face of the brother who always greeted Glaziev so politely.
Estrogen Brigade: The manga's demographic is seinen, but it enjoys a very large female fanbase, due in no small part to the very attractive male characters, strong female characters, equal-oppurtunity fanservice, and unapologetic Ho Yay.
Germans Love David Hasselhoff: The series has attracted a decent fanbase in the States. The manga's use of popular western tropes (and slight similarities to other popular shows like Baccano! and Black Lagoon) might have a role in this.
Striker comes off as a Depraved Bisexual with a homicidal obsession with the object of his affection, Marco, and a lot of his violence towards Constance comes off as...not even jealousy, more like a vengeful Murder the Hypotenuse.
Jerkass Woobie: Surprisingly, Worick. While he was an adorable, educated rich kid, he was also the son of a mistress, his father beat him, the maids gossiped about him constantly and to top it off, his bodyguard was a deaf kid who was the resident Woobie. This gave Worick an enormous chip on his shoulder.
Nicolas' superior/father officially needs to die after what he said to the boy at the end of Chapter 15.
In Chapter 20, Ivan Glaziev forces a Twilight to attack Loretta by holding his wife and daughter hostage. When the Twilight fails to kill her and is later lying in a pool of his own blood, Glaziev tells him that his family was stripped naked, had their limbs chopped off almost immediately after the Twilight left for the Cristianos' safehouse. There... are no words.
Nausea Fuel: Invoked by the author through her creating colossal amounts of Mood Whiplash between the few short scenes that go back and forth between Worick flirtatiously kissing a woman who'd hired him and a man who begins to do so forcibly to a woman next to a pile of dismembered Twilight corpses.
The flashback chapter showing a little tagged girl crying over the beaten and raped corpse of what is most likely her mother. The last panel shows a bunch of hands most likely reaching for her. Thankfully, that's the last we see of it.
Striker. He was the oldest and most experienced of the Destroyers, and he is...just... yugh. The best way to describe him is that, if he were a hero, he'd be insanely popular. He acts a lot like Worick, really; he's chill, easygoing, loves fun, is a smartass, is a bona fide hunk, and will casually flirt with both men and women. If you're a normal human, he's perfectly polite to you. If you are a twilight, he will get his rocks off by murdering you in cold blood simply to kill time. In his Enfant Terrible youth, he was absolutely horrifying in the sheer glee with which he brutally murdered hundreds of innocent civilians—man, woman, and child, all graphically and almost all of them screaming, running away, and begging for mercy. He's no different as an adult, just calmer about it. This is before you factor in his chilling obsession with Marco that causes him to deliberately torture him both physically and psychologically. Even the other Destroyers are afraid of him. The only reason he doesn't qualify for Complete Monster is because he was brainwashed in a government lab to be exactly what he is.
Too Bleak, Stopped Caring: As the plot progresses, the manga takes a very sharp turn into Darker and Edgier territory, with lots of character deaths and personal drama being thrown around. This has chased away early fans of the series, who liked the initial (relatively) lighthearted tone of the early chapters.
Unintentionally Unsympathetic: Marco, mostly because he's where most of the sympathetic points are thrown in the CURSED novel that explores his backstory. He is the only second-gen Destroyer to question whether their mission's rapidly rising body count is in line with what their superiors told them about twilights being monsters. But mind you, he has murdered literally hundreds of screaming and crying people by the time he starts voicing his doubts. It makes it hard to welcome him over to the side of good, even when his monstrous acts pale in comparison to his fellows' slaughterfests.
The Woobie: All Twilights could classify as this, considering the discrimination and abuse they suffer on a daily basis, but Nicolas is the biggest example. He's an orphan, beaten up and made fun of by most of his superiors, he's been deaf from presumably birth thanks to the actions of one of his parents, and he doesn't even expect to live very long. It's no big surprise why he's such a jerk in the present. And in the present, he is treated more like an animal than an underling. He won't even sit on a chair or bed, instead sitting on the floor with his knees pulled up to his chest. The scene where he starts to pass out and shake due to withdrawal, and the mercenaries inject him with meds is hard to read. The way they're slapping him to keep him conscious and standing him up so he's presentable in front of an approaching Wallace is disturbing.
, the opening has gotten a lot of deserved love for its style and general awesomeness.