Joker

is a wanted criminal, who poses a major threat against the Special Fire Brigades.

Appearance
Joker is a tall man who appears to be in his early adulthood. He has long and stringy black hair that falls below his neck and a spiral-shaped iris. Joker's outfit resembles that of a cowboy. It consists of a black top-hat and a patterned black bandanna across the left side of his face, covering his left eye, an old-fashioned shirt with a black waistcoat, white trousers and shoes. The man is commonly seen smoking a cigarette and appears to always carry a sadistic expression.

Personality
Joker is sadistic, he enjoys hurting people and toying with their emotions. He's also willing to offer information to his opponents, in exchange for entertainment. He is charismatic and knows how to sway people to join his cause. Joker also has high expectations for Shinra and wants him to become the "Devil" and uncover the truth, hidden by Special Fire Brigades. He tends to speak of members of Special Fire Brigades as model firefighters.

Abilities
Joker has adapted to the Human Body Ignition Phenomenon and was granted the ability to manipulate flames. He uses the his lit cigarette to create various shapes in the form of letters, suit of cards or card-shaped projectiles. He also uses bottles of explosive substance, which can create instantaneous explosions or cause things to burst into flames. He is skilled in hand-to-hand combat, as demonstrated by effortlessly dodging most of Shinra's fiery kicks with ease, as well as keeping the boy on his toes the entire time. Joker is also fast, capable of catching up to Shinra, who was using his ability to accelerate himself. In the midst of battle, he can notice movement as simple as change in trajectory, making him observant and sensitive to his surroundings.

Introduction arc
After the 8th Special Fire Brigade finishes their assignment, Joker uses a powder-like substance, he received earlier from an associate, to force the building's ceiling to collapse, but the brigade manages to escape unscathed. Joker later intrudes on the Fire Officer Newcomer Tournament, where he assaults two members of an unspecified brigade in the Haijima Heavy Industries. He gets spotted by Shinra, which leads him to taunt the boy about his past and truth behind the death of his family. When the man threatens to kill the innocent bystanders, Shinra attacks him with a barrage of kicks, but Joker manages to dodge them all with relatively ease.

He then picks up a bottle and uses it to cause an explosion. Using it as a diversion, Joker heads in for an attack. The man then throws card-shaped projectiles, injuring Shinra. He steps up, wondering whether he should kill Shinra, and notices his opponent's expression, leading him to reveal that Sho is alive. Joker informs Shinra that the Special Fire Brigades are hiding something from him. Shinra, however, attacks Joker, but does not manage to connect a single kick. When Tamaki and Arthur show up, Joker attempts to get rid of the two, but to no avail. He then uses the explosive substance as a diversion and flees, encouraging Shinra to show his dedication to everyone and offering him the chance to join Joker's cause.

Sentient Flame Human arc
The next day, Joker becomes a wanted criminal and discusses the events of the tournament and the 8th Special Fire Brigade with his partner.