Rei Oogami (大神　零
The protagonist/antihero. Ogami Rei is a mysterious young boy about whom not much is known. Sakura first witnesses him burning people with a blue flame in a park; the day later he transfers to her school. When Sakura confronts him about his killings, Ogami reveals to her that he's in fact a "Code:Breaker", a secret government agent who punishes those who can't be punish by the law. His code number is 06, meaning he's the weakest member of the Code:Breakers. He believes strongly in the idea behind the Code of Hammurabi, often citing the quote "Eye for eye (目には目を, Me ni wa me wo?), Tooth for tooth (歯には歯を, Ha ni wa ha wo?)" and adding on "EVIL for EVIL (悪には悪を, Aku ni wa aku wo?)

Externally, Ogami is an aloof, uncaring person who is whole-heartedly dedicated to punishing evils and cares for not much else, but Sakura gets closer to him she realizes that his actions often belies his cruel words. Ogami's power lies in his left arm, which burns anything he touches with a blue flame.

Sakura Sakurakouji (桜小路　桜
Sakura, is thought of as cute and helpless by boys who think they should protect her, but she's actually a martial arts expert and turns down guys who ask her out because they don't know the real her. Prior to the storyline, she found an old dog whose homeless owner had died a few months before the start of the story. She attempts to befriend the dog whom she promptly names "Dog". Her attempts are fruitless until Oogami comes. She is apparently an exception to Rei's fire and cannot be burned. Sakura disagrees strongly with Oogami regarding his views on people, specifically criminals, and that they are trash who need to die.

Toki Fujiwara
Code: 04 of the Code Breakers. Toki's power revolves around magnetism, but later on he also exhibits the ability of mercury manipulation. When he loses his power, he takes the form of his younger self. He's the joker of the group, always fond of teasing people and has a propensity to tell outrageous lies (which fool no one but Sakura), but gets serious when it comes to his sister, Nenene's, safety.

He follows the Hammurabi code variation of "an eye for an eye, a tooth for a tooth and the hammer of justice for the wicked".

Rui Hachiouji (八王子 泪
The Code:05; she's hailed as one of the most powerful Code:Breakers. At first, Sakura thought she was a man, but she is actually a woman. Rui acts very much like a tomboy but is truthfully immensely shy. She is one of the few to know Shibuya's true identity and often uses this secret to blackmail him. Her addition to the Code of Hammurabi is "and the punishment of death for evil".

Rui's ability allows her to manipulate her shadow to defend or to attack by slicing others shadows (the damage done to the shadow becomes real). Her most powerful technique is "Empress Paradox", a shadow monster which envelops her body and can even eats up Rui herself. When Rui loses her power, she becomes a mermaid.