Suman Dark is an exorcist. He is a member of The Black Order.
Suman Dark's past was presumably a normal one, however 5 years before his introduction into the story, he was found to be an accomodator for Innocence. He was asked to Join the Black Order, which Suman had no interest in but when offered the necessary money to pay for his sick daughter's medical expenses, he could not refuse and agreed to join. He made 1 noteworthy friend, Johnny Gill.
In human form, Suman Dark appears as a young man man with light skin and average build. He has slicked back black hair with a section dangling in the front. He wore the standard Black Order Exorcist Uniform.
As an Awakened One, Suman Dark's appearance resemble's a human's in the most vague of ways. His body enlarges to the point it was nearly the same size as a small mountain. It is one gigantic arm-less and leg-less torso of a light gray complexion, lighter than that of the Noah. A giant Golden Halo looms over his headless shoulders. Additionally, on the left breast lies a smaller body. This is Suman Dark's Original body merged with the the giant one. This one hosts a normally shaped human figure from the waist up but is bald, pupil-less and shares the same unnatural complexion as the larger body.
Suman Dark was an ordinary man who did not desire power, rather his attention was with his family, particularly his cherished daughter. He joined the Order for her sake alone so that he could pay for her expenses. Suman Dark could be perceived as a coward because at great cost, he betrayed the Black Order and leaked Information in order to save his own life, but it should be noted that he had no love or particular loyalty to the Black Order anyway and only joined because he needed the money for his daughter and this was known about him from the beginning.
Jamie Dark - Suman Dark's beloved child. He only became an exorcist for Jamie's sake.
Winters Sokaro - The General that Suman Dark served under. It's unclear how deep their relationship went but Sokaro mocked him and his comrades even in death.
Johnny Gill - Perhaps the one friend he made at the Black Order. They regularly played chess together.
Suman Dark was sent out on a mission with 2 of his fellow Exorcists, however their leader General Winters Sokaro could not be on the mission for unknown reasons. The trio of Exorcists met misfortune when they encountered Tyki Mikk, a member of the Noah Family, the enemies of the Black Order. Despite their power as Exorcists and 3 no less, they could not beat the far more powerful Noah and both of Suman Dark's comrades were easily killed. When it came to Suman Dark's turn, he begged Tyki for mercy. He did not care about the Black Order's Agenda to begin with and when Tyki agreed to spare him on condition he provide intelligence on his own allies, Suman Dark agreed.
Tyki was true to his word and spared Suman Dark with no strings attached with the exception of leaving a Teez Butterfly inside of Suman Dark that would remain dormant normally but eat him alive if he betrayed them. But it was not Suman betraying the Noah that would bring disaster. The direct effects of Suman's information leak caused the deaths of 148 Black Order members including 6 Exorcists, which were already in an extreme minority in the Order.
Suman lost consciousness after the encounter with Tyki but was found and taken to a nearby village and was treated. But what Suman did not know was that his own Innocence had determined that Suman Dark was a traitor, a heretic and unworthy of the power or position of an Exorcist. When he awoke from his unconsciousness, he was no longer even human. He had taken the form of a massive grotesque monster. This was the form of a "Fallen One" or one who had betrayed God. At this point, Suman Dark was not even in control of himself any more and his new monstrous form began wrecking havoc to the town he was unfortunately nursed at previously. Allen Walker and Lenalee Lee found Suman Dark after following an Army of Akuma that were attracted to the massive Aura of Suman's new form.
The sympathetic Allen went to lengths to save Suman Dark and was sucked into the massive body. Once inside, Suman Dark's sin was shown to Allen. Allen fought a hard battle but managed to defeat Suman Dark with extreme effort, using the maximum power of his Innocence Cross and damaging it in the process. In an attempt to save Suman, he took his still present Innocence Shard out of the body. He then managed to extract Suman's morphed yet original body out of the behemoth monstrous one. Even though Suman had technically been saved and his innocence preserved, his mind was dead. Not wanting a complete failure, Allen expressed his with to deliver Suman Dark's body to his wife and child, however the Teez that Tyki had placed inside Suman previously suddenly took effect and consumed the body completely. It was a sad and tragic end for the Exorcist.
Suman Dark had an unnamed parasitic type Innocence with unknown abilities. However in the anime it displayed Wind Based attacks.
A technique that draws in and manipulated the air around Suman Dark's Innocence arm and allows him to manipulate it to some extent. He fired a wind blast powerful enough to destroy a level 2 Akuma with ease.
Suman Dark's form as a Fallen One was a gigantic limb-less monster. In this form he possessed a high level of raw power and could should large blasts of energy from his amputated arms. Additionally he could levitate in this form.