Jack Deamon (ジャック＝デイモン) is a foreign hitman, who was hired by K. He has an impulse problem which he corrects with medication during his mission. He also has two unique tattoos on the back of his hands and he is also able to speak Japanese. He is very skilled marksman, a former member of S.W.A.T and an internationally wanted criminal. He was finally killed by Ryunosuke Takagi.
Jack has slicked back light hair and glasses. He is seen wearing a black suit and the same colored tie. Over the suit he wears a long coat, which hides many of his weapons beneath it, along with storing his medication. Jack has two tattoos on his hands. His left hand has the tattoo of a butterfly and his right one a tattoo of a flame kind of image.
After his second encounter with Falcon, he lost his right hand to make his escape.
Jack Daemon appears calm and professional at first, but there is more to him. He used to have troubles with his impulses, as he often killed people he was not even suppose to. But now that he has been re-employed as a hitman, he has a medication to keep his impulses under control. The bad side is, that he needs to keep upping the dose. The impulses are so strong that when he ran out of medication, he was forced to cut his hand open to prevent himself from killing Haruka Takagi and her doctor. Jack does his best to complete his jobs, he has even sacrificed his right hand to escape from Falcon.
Jack is first sighted when he is targeting Professor Shikimura's life from the opposite rooftop, while the Professor is seeing Ryonosuke. Killing the professor before hiding from the police, who chase after Ryonosuke after he
escaped from the scene.
Jack is listening on the otherside of the door, while Fujimaru is questioning Maya's alibi on the christmas day. As Fujimaru leaves, Jack asks if it will be fine with Fujimaru suspecting Maya. Maya is not worried, she is more interested to know what became of Jack's target. Jack confirms on killing Proff. Shikimura.
Jack kidnaps Haruka and Haruka's doctor, Dr. Tominaga from the doctor's home. He shoots Hosho on her chest with a magnum. Not checking if she is dead, he leaves her there while taking those two with him. Having tied Haruka and Dr. Tominaga up, he calls Fujimaru from Haruka's cellphone. Telling Fujimaru to hack into into a transformer's substation if he wants to see his sister again.
Maya calls Jack again, once Fujimaru and his friends have left to find Haruka. Telling Jack to abide by the contract and not kill the two. While he is allowed to kill Dr. Tominaga, if Fujimaru fails to hack into the Transformer's substation. Jack hungs
up and walks over to Haruka and Tominaga.
- He is played by TET in the live action drama. His name has been changed to Joichi Demon.
- He is 180 cm tall and he is in the AB blood group.