Hellfire Flame

Hellfire Flame (業火のフレイム, Gōka no fureimu) is a ninja partner of Gale Wind who comes from the same 37th graduating class like Gale Wind. In the past, they joined the Monster Association to become stronger.

Appearance
Hellfire Flame is a tall man with a muscular build and styles his black hair in spikes with the tips bending down. His face is angular with thick eyebrows and has a black marking over his left eye.

Hellfire Flames attire consist of a sleeveless black shirt and pants, a white vest with spiky collar and flame design, black arm warmers and braces on his forearm and neck.

When he transforms into a monster, his teeth become sharp and he has pulsating veins.

Personality
Hellfire Flame is shown to be calm and serious most of the time.

Monster Association Arc
Hellfire Flame and Gale Wind attack Speed-o'-Sound Sonic in a forest as a form of skinship and introduce themselves as Sonic's senior form their ninja village. After some discussion, Hellfire Flame and Gale Wind invite Sonic to join the Monster Association to further their goal of becoming the rulers of the World. They reveal their plan to attack the Hero Association, more specifically killing Flashy Flash and asks Sonic's help to distract the other heroes. When Sonic refuses, Gale Wind transforms into a monster and demonstrates his speed, shocking Sonic and Hellfire Flame explains the process of the transformation, showing his own monster form. They then offer a Monster Cell to Sonic and leave.

He and Gale Wind are present at Gyoro Gyoro's speech.

Abilities and Powers
As a graduated ninja from Sonic's village, he is shown to be an immensely powerful like his partner, Gale Wind. Coming from the "Golden" 37th class of the village, he is no doubt an even greater ninja than Sonic and thus could qualify for the S-Class rank of the Hero Association if he had joined them instead.

Physical Abilities
Immense Speed and Reflexes: Being from a ninja village, Hellfire Flame has superhuman speed that even surpasses Sonic's. He and Gale Wind were able to surround Sonic and strike him continuously before the younger ninja could react in his human form.

Transformation: Hellfire Flame can change into his monster form and revert back to his human form freely. According to himself, he achieved this through ninjutsu training.

Fighting Style
Master Ninja: As a graduate of the ninja village Sonic hails from, Hellfire Flame is skilled and masterful in ninjutsu. Having graduated among the "Golden Class" that is renowned as the best the village has produced, Hellfire Flame is without a doubt a greater and more powerful ninja than Sonic.

Trivia

 * In the webcomic, there is a monster named Hellfire with a partner named Gale who also tries to kill Flashy Flash. Whether or not this is the same character is unknown.