Jack Dio (Earth-616)

Early Life[]

Jack "Jackie" Dio evidently has a long and sordid history. At some point, he worked for Silvermane alongside his father, a criminal who died after wearing a super suit that blew up on him while fighting a superpowered foe.^[1] Forced now to take care of his brother Vince, he developed a great hatred for superhumans and ofted got into arguments with his brother who instead wanted to invest in superpowered criminals. During that period he also survived a Punisher attack that left him as the only survivor.^[2] He and his brother eventually had a falling out which led to Vince sending a group Hydra assassins after him but the assassination attempt failed. Jack managed to track down his brother and beated him to a pulp but was unable to kill him due to the fact that he had swore to his father that he would have protected him. Jack therefore decided to simply banish him out of New York.^[3]

During that time, Hammerhead killed Underworld’s best friend a hood known only as “Joey D”) – because Joey owed the crime lord two grand.^[4] Before he could exact revenge, Underworld was incarcerated after being lured into a trap by his brother and being defeated by Spider-Man^[5] and spent about ten years in prison.^[3]

Release from Prison[]

After being released from prison he visited his old boss, Silvermane, to look for work but instead found him as a bedridden cyborg. Silvermane told him to seek out the Owl for work which he did but after arriving there he found out that his superior in the Owl's organization was his brother Vince, now a superpowered villain going by the name of "Mr. Pain".^[3]

Vince proceeded to beat him up for what Jack had done to him and as a form of revenge banished him from New York. Jack then woke up in a hospital where all the patients were his brother's victims. There he learned that the Owl was receiving a shipment at the docks that night. He decides to steal it but the shipment turns out to be some type of gas that leaks out of the canister and knocks him out.^[5]

Jack stumbles to Satan's Circus to look for a doctor but soon after finding one willing to help he passes out again. Jack wakes up to see the doctor pointing a gun at his head but manages to dodge the bullet and finds out that the gas was SSS.2, a gaseous variant of the Super-Soldier Serum, which had granted him peak human abilities. The doctor also gifts him a pair of glasses that enhance his sight. Jack then attacks a night club owned by the Owl but he is defeated by the Boomerang and the Grizzly. Still, he manages to run away and seeks a man called "the Mechanic" who can supposedly get him better equipment.^[2]

The Mechanic explains to him how his glasses work and gives him a titanium-lined coat and a pair of smart guns that shoot Adamantium bullets which he uses to defeat Boomerang and the Grizzly but he is attacked by the Punisher before being shot by the police. He wakes up in the hospital and is injected with a serum that grants him a healing factor by the doctor to save his life while the hospital is attacked by a group of supervillains hired by his brother to kill him.^[6]

Healed by the serum Jack easily takes out the criminals and meets with the Owl, who wanted a truce but they are attacked by Mr. Pain. Jack manages to use his equipment to defeat his brother and shoots him in the head, killing him but is handed a bill by a courrier for some services that he hasn't received. Jack follows the adress on the bill and discovers that the man that had sent it was the Consultant, a man that provided equipment and powers to criminals and that he was actually both the doctor and the Mechanic and that he had turned Jack into a supervillain to kill his brother, who had refused to pay him after getting his powers. The Consultant renames Jack as "Underworld" and suggest to him to pay up to avoid his brother's faith. Jack eventually does so by killing two thieves and stealing their loot, finally embracing his new Underworld identity.^[1]

Civil War[]

Underworld began working for his old enemy, Hammerhead. Hammerhead was attempting to organize a criminal syndicate, allegedly to oppose the recently passed superhero registration act. His real motive, however, was to steal territory from the imprisoned Kingpin. When the villain Slyde refused to join Hammerhead’s organization, Underworld shot Slyde in the back of the head, killing him in cold blood.^[4]

Later, Underworld helped Hammerhead organize a meeting with over a dozen costumed criminals. The gathering was raided by Iron Man and S.H.I.E.L.D., who had been duped by the Kingpin into thinking that the meeting spot was a hideout being used by Captain America and his Anti-Registration Underground allies. During the ensuing battle, Underworld ambushed Hammerhead and shot him in the back with adamantium bullets. Hammerhead survived, but Underworld visited him in the hospital and revealed that he was working for the Kingpin. He was also still angry over the death of Joey D. Underworld then killed Hammerhead by putting an adamantium bullet into his brain.^[4]

• Super-Soldier Serum: Underworld possesses a variety of heightened abilities as a result of being exposed to a gaseous variant of the Super-Soldier Serum that first produced Captain America called SSS.2.
  
  • Peak Human Strength: Underworld's physical strength has been increased to the peak of human capability. While he isn't superhuman, he is as strong as a human being can be and can lift approximately 800 lbs.^[7][8]
  • Peak Human Speed: Underworld's running speed is also increased to the maximum of human capability and can run at a top speed of about 30 miles per hour.^[7][8]
  • Peak Human Stamina: The serum has increased the efficiency of Underworld's musculature to the point that it produces less fatigue toxins than the musculature of most humans. He can physically exert himself at peak capacity for about 1 hour before the build up of fatigue toxins in his blood begins to impair him.^[7][8]
  • Peak Human Durability: While Underworld still has the same physical vulnerabilities as other humans, his body is more resistant to injury and disease than most other humans.^[7][8]
  • Peak Human Mental Process: Underworld has also been mentally enhanced by the serum, and can think as well as mentally respond at speeds which are at the pinnacle of human perfection. It is also possible that he has a photographic memory.^[7][8]
  • Peak Human Agility: Underworld's agility, balance, and bodily coordination are also increased to levels that are beyond the natural physical limits of any Olympic athlete that has ever competed, though they don't reach superhuman levels.
  • Peak Human Reflexes: Underworld's reflexes are similarly enhanced and are at the peak of human potential.^[7][8] He is capable of dodging bullets at close range.^[9]
• Regenerative Healing Factor: After being shot by the police during a standoff with the Punisher Jackie was visited by the Consultant in Rykers infirmary and injected with a serum that gave him a healing factor. The full limits of his healing factor aren't known, but he can rapidly regenerate damaged bodily tissues much faster and more extensively than any normal human. For example, he can fully heal from multiple gunshot wounds within a matter of moments. Due to the efficiency of Underworld's healing factor, probably also renders him immune or more resistant to disease, drugs, and toxins and suppresses his ageing process, as with Deadpool and Wolverine. It is unknown if he's able to regrow lost or severed limbs, but he was shown being able to regrow his teeth, having lost them in his encounters with his super-powered younger brother, Mr.Pain, and Punisher.^[7][8]

• Hand-to-Hand Combat: Underworld is a formidable hand to hand combatant, particularly when using street fighting techniques.^[10]
• Marksmanship: Underworld is also an expert marksman.^[11]
• Tracker: Underworld seems to be able to track others very well, which was evidenced when he was able to track both his brother Vince, and Hammerhead.^[7][8]

• Special Sunglasses: Underworld possesses a pair of sunglasses that are composed of an extremely durable, though unidentified, substance. Through some unexplained technology, the glasses are connected to the bullets that he fires from his gun. The glasses lock onto a target and once he fires the bullets, they'll follow a target no matter what the target does to get away, even if he/she runs around corners.^[7][8]
  • Enhanced Vision: The glasses enable him to see in the dark perfectly via infrared imaging and allow him to track targets through the heat released by their body.^[12]
• Titanium Lined Coat: Underworld almost always wears a long, calf-length coat that's lined with titanium, rendering most of his body highly resistant to most forms of conventional physical attack.^[7][8]
  • Superhuman Durability: His coat allowed him to survive an explosion completely undamaged and protected him from Mr. Pain's blows.^[13]

Pistols: Underworld carries a pair of advanced pistols capable of firing adamantium rounds.

• When Underworld first reappears, Hammerhead introduces him as "an old kid who just got out of stir and re-entered a very new game..." Other comments in the issue point at his past as a Silvermane enforcer.^[4]