Justice Devil

The Justice Devil (正義の悪魔) is a Devil that embodies the fear of justice. He is the secondary antagonist of the War Devil arc.

Appearance
The Justice Devil’s true appearance is unknown.

Personality
Nothing is known about the Justice Devil's personality, except that he tends to contract with anyone who sees their actions as "right" and "justifiable" (such as the class president and Yuko) regardless of the actual morality behind their actions.

History
At some point, the class president made a contract with Justice Devil for an unknown price, because she was jealous of her classmate, Asa Mitaka for capturing Mr. Tanaka's attention due to her aloofness, and the lack of socialization in their class. Mr. Tanaka was also having an affair with the class president, but it's unknown when it started.

War Devil arc
After Asa accidentally killed Bucky, the class president and Mr. Tanaka decided to walk with her to his grave at night in hopes the spirit of him would've forgive her for killing him.

On the way there, Mr. Tanaka, and the class president cross the street, and Asa stays behind. The class president realizes it's because Asa won't cross the street without the green traffic signal and begins to berate her for it for being a goody-two-shoes. She suddenly mutates into a being made of muscles and reveals that she made a contract with the Justice Devil, claiming that she and Mr. Tanaka had been having relations, but he had a thing for her, which held them back. Because of this, the only way for them to be happy is to kill her. She also reveals that her plan was for Mitaka to kill Bucky in order to humiliate her.

The class president is later killed alongside with Mr. Tanaka by the War Devil after it took Asa's body. Later, Yuko made a deal with the Justice Devil, which allowed her to read Asa's mind.

Abilities
As a Devil, the Justice Devil possesses all of the standard devil abilities. These include the ability to make contracts with humans. The contracts with it seen so far are those with the class president and Yuko. Unlike the other devils, the Justice Devil seems to ask no price in exchange for his contract; Yuko tells Asa that the price for her contract is only to receiving "a heart that shines with justice".

Devil Powers
Justice Empowerment: The Justice Devil can transform the sense of justice of anyone who contracts with him into power. This power seems to vary according to the sense of justice who made the contract:


 * The contract with the class president, who wished to have a happy ending with her teacher, gave her the power to transform her body into a blob of flesh with multiple heads, large muscular tentacles with claws-like fingers and superhuman strength. While in her transformed state, she is able to move very quickly, being able to attack in just seconds and she was capable to slice though Asa Mitaka's skull and flesh, killing her instantly.


 * The contract with Yuko, who wished to punish the bullies who persecuted Asa Mitaka, gives her the ability to read others' minds and detect their inner thoughts and feelings. The contract also allows Yuko to transform into a thin and gaunt being with an uncovered brain and tentacles instead of legs.

Trivia

 * The Justice Devil is based more on one one’s own personal sense or “idea” of justice rather than actual justice itself. The transformation of the class president shows numerous heads, as if to symbolize that the idea of justice has "many faces", varying according to each person's personal perspective.
 * The price of the contract with the Justice Devil ("a heart that shines with justice") is likely to be some part of the user's personality or understanding of right and wrong to be altered. As shown, the personalities and sense of right and wrong of Yuko and the class president appears to have been grossly and unknowingly altered, deformed or radicalized by the Justice Devil as the actual "price" for their powers.