Edgar Chang Martin (エドガー・チャン・マルティン, Edogā Chan Marutin) was the Assistant Chief of the Asia Branch of the Black Order, husband of Tui Chang, nephew of Zuu Mei Chang and father of Bak Chang. He, like his wife, played a large role in the Second Exorcist Program until his death.
Edgar would pass on his looks to his son, including his fair hair and softer facial structure, though unlike his son, Edgar was tall. He was typically seen wearing a lab coat with no embellishments over a white dress shirt, black vest, tie and dark dress pants. It is noted that he would have looked a bit more handsome if he hadn't let his hair get long and messy. Edgar looks younger than his age, a trait of the family.
Unlike his wife, Edgar was laid-back and a bit of a pushover. Like the other members of Laboratory 6, he cowered in fear when his wife was angry at him, though he did adore her. He was shown to be a bit awkward with children, as seen when he attempted to explain childbirth to Yu Kanda, though he did care for Kanda and Alma Karma, trying to comfort them both when they needed it and worrying about their health, especially when Kanda collapsed after his hallucinations took a turn for the worse. Like his wife, Edgar is shown to bear a lot of guilt for participating in the Second Exorcist Program, shedding tears when Alma called them (he and the other scientists) 'animals' and found out about the bodies of the original Exorcists his and Kanda's brains had been harvested from.
Edgar's marriage to Tui, to whom he was distantly related, was arranged before either of them were born. Edgar fell in love with his fiance before marrying her. He fathered Bak Chang at age 23 with her. Because he was a member of the Chang family, he was a major player in the Second Exorcist Program. During the program he took a fancy to the artificial children who were born in the laboratory.  However they all started to have hallucinations of their previous life and death and needed to be "put back to sleep".
Encounter with Alma and Kanda
Edgar is first seen when Alma Karma is helping Kanda out of his birthing tank, Edgar ordering a lab assistant to inform Tui of Kanda's awakening and then taking off his coat so Kanda could have something to wear and reprimanding Alma for wearing so little in the cold room.
Later, when Kanda and Alma get into one of their many fights, Edgar is one of the several hurt trying to break them up, laughing his injuries off when his wife takes note of them and then cowering when she glares at him. When Kanda calls Alma a 'stalker' and a 'weirdo', Edgar just laughs sheepishly and wonders where Kanda learned how to talk in such a way.
Edgar then shows Kanda to the containment room where he was 'born', explaining that all of the other holes in the room held sleeping Exorcists just like Kanda. When Kanda asks him if humans are born in a similar matter, Edgar explains that normally, humans are born from mothers, and that Tui is also a mother. Kanda, though, misinterprets and asks, in shock, if Edgar was born from Tui. Edgar then awkwardly begins to give Kanda 'the talk', though their discussion is first interrupted by a call on Edgar's communication golem, then by Kanda becoming distracted when he sees a hallucination.
Nearby, Alma catches their attention when he sneezes, and when Kanda runs off, refusing to acknowledge Alma, Edgar stays behind to console a now upset Alma. He is seen as one of the ones advising Alma to read a book given to him by one of the lab technicians, "With This Book, You Can Make 100 Friends! Revised Edition," in hopes that Alma and Yu will become less awkward around one another.
Later, when Kanda's hallucinations begin to take a turn for the worse, Edgar is first seen hovering at his bedside worriedly, then talking to Sahlins Epstain, Renny Epstain and his wife, Tui, gravely, informing them that Kanda informed them that he has been seeing "people and places unknown to him". The four of them then decide that, following policy, Kanda will have to be "disposed of", unaware that Alma has heard them.
Unlike his wife, Edgar was not present for Kanda's magic-induced euthanasia; he was hunting down Alma, who was attempting to find the Innocence the scientists had been attempting to forcibly synchronize him with so he could save Kanda. When Edgar attempts to stop Alma, Alma calls Edgar and the other scientists animals, an accusation which hurts Edgar. As Alma falls down the hole in the room to find the Innocence, Edgar mutters Kanda's name and screams out in agony as he sheds tears. Edgar attempts to order the CROW who find Alma via golem to not attack Alma, but a now injured and maddened Alma Karma manages to synchronize with the Innocence he has found and kills the CROW.
Edgar is not seen again until Kanda escapes his confines and goes looking for Alma, carrying an injured Noise Marie into the Second Exorcist containment area to find that Alma has slaughtered the sleeping Second Exorcists and the staff of Laboratory 6, Edgar's dead, bloody body dangling from the Anti-Akuma Weapon that has grown off of Alma's arm and stabbed Edgar through the back, yanking him clean off of his feet. In the anime, Edgar was the one searching for Alma throughout the branch after he killed the CROWs, and although soon he finds him in the laboratory among the slaughtered staff members, it seems that he tried to talk to him and embraced to calm down, but failed to do this, becoming another victim of Alma.
Alma and Kanda fight, Kanda being forced to kill Alma so he can live and try to find the woman he has been having hallucinations of. Later, For is seen carrying Edgar's corpse, musing on whether or not the Second Exorcist Program will finally be shut down and tearfully remembering how Tui had ordered her not to intervene with Alma's rage. For concludes that they were all fools and crazy for turning down the "protection of a guardian angel", then set Edgar's body down by the corpse of his wife, arranging them so they are propped up against a wall and leaning against one another, holding hands.
Artificial Exorcists arc
After Allen Walker and Road Kamelot were accidentally sent into Yu Kanda's memories by Wisely, they witness the events behind the Second Exorcist Program firsthand and saw the laboratory members, including Edgar.
When Tokusa is taken over by Alma Karma cells, Alma's mind mistakes Bak Chang (who bears an uncanny resemblance with his father) for Edgar. Fueled by his hatred of the scientists because of what they did to him, the cells cause Tokusa to attack Bak.
- The Author was a bit disappointed Edgar did not have that much success.
- Edgar disliked haircuts.