Jack of Hearts's History
Jack Hart was the son of Phillip Hart, a brilliant scientist who developed a revolutionary, extremely efficient liquid fuel called "Zero Fluid," and a humanoid alien woman of the Contraxian race. The alien was one of many scientists dispatched to try to discover an energy source to resuscitate the dwindling nuclear processes of the Contraxian sun. Learning of Hart's experiments, the alien assumed a totally human form to keep Hart under surveillance. Hart and the alien eventually met, married, and produced a son they named Jack. The alien woman, "Marie," died in a car accident when the boy was a child. Neither her husband nor child ever learned of her extraterrestrial origin.
When Jack was a teenager, Phillip Hart perfected his "Zero Fluid" and decided to donate the fuel to all the free countries of the world. Hart was then contacted by agents of the criminal Corporation who wanted to market the Zero Fluid. Refusing to deal with them, Phillip Hart was murdered by Corporation agents before the eyes of his son.
Managing to escape, Jack Hart took refuge in his father's basement laboratory Corporation agents broke in minutes later, and their laser-cannon sheared through the laboratory door, striking the vat of Zero Fluid. Doused by the powerful, corrosive fuel, Hart underwent a mutagenic change and began to glow. With an uncontrollable burst of energy generated by his entire body, Hart killed his father's murderers. Vowing vengeance on the entire Corporation, Hart fashioned a costume for himself, plundering his father's collection of armament. The armor somehow interacted with the final stage of mutation and provided a moderator that contained and controlled the release of his body's energy.
Calling himself Jack of Hearts as a tribute to his father's passion for playing cards, he embarked on a mission of vengeance. Initially his quest for vengeance on the Corporation was blind and intolerant, leading him into conflict with such innocents as the Sons of the Tiger and the Hulk. Later he aided Iron Man in freeing Stark International from takeover by Mordecai Midas, and was taken under Iron Man's tutelage for a brief time. When his energy powers began to increase uncontrollably, he placed himself into SHIELD custody. There he met a former classmate of his, Marcy Kane, who was also actually a Contraxian. She revealed to him his mother's extraterrestrial origin and convinced him to accompany her back to Contraxia to try to save their sun. On Contraxia, a cult calling themselves the Survivalists captured Jack of Hearts to force him to do what he was intending to do anyway. He was flown in a starship to Contraxia's sun and there vaporized the craft before sending the energies of his body into the sun. In some as yet unknown manner, he apparently restored the vast quantities of hydrogen necessary to sustain the nuclear reactions of the sun, and added an undisclosed number of years to the sun's life. Then, still radiating great energy, he returned to Contraxia, his vast heat melting the polar icecaps, in order to say farewell to his girlfriend and to lecture the Contraxians about morality. He then flew off into outer space, realizing that he could no longer live among organic beings with his vast energies emanating out of control.
Captured by the Stranger
Under unrevealed circumstances, Jack of Hearts was captured by the enigmatic alien, the Stranger, and placed on his planet for study. Jack of Hearts was inadvertently freed by the Avenger Quasar, who had traveled to the Stranger's world for his own purposes. Joining other refugees of Earth, Jack of Hearts returned to their native planet, only to be mind-controlled by another refugee, the Presence, into fighting Quasar. His armor was breached in the fight, and Jack appeared to have exploded in a burst of Zero energy.
Actually, Jack was rescued and healed by the Moondragon, in her bid to gain an ally to prove herself as a worthy consort for Quasar. Jack proved overzealous as a mentally-influenced agent of Moondragon, who soon abandoned her designs on Quasar anyway, and Jack was released from her control.
Jack sequestered himself in the abandoned Hart residence, but found his condition rapidly deteriorating, as his energies again threatened to go out of control. Returning to space, Jack sought out the alien Silver Surfer for help. The Surfer led Jack to an alien armor-wielder, who created a new and better energy-regulating armor for him. Jack remained with Surfer for a short time, and both teamed up with other cosmic heroes when they encountered the mega-powerful entity known as the Tyrant. The battle left Jack of Hearts severely weakened, and he was nursed back to health by fellow adventurer Ganymede, whereupon the two became lovers.
Ganymede was the last member of a sisterhood dedicated to the opposition of Tyrant. She refused to engage in physical intimacy, which was not an option for the armor-bound Jack. She was also at one point willing to abandon an injured Jack rather than let her enemy escape. Although Jack remained by Ganymede's side for many months, they eventually went their separate ways.
While journeying through space, Jack of Hearts happened upon agents of the cosmic beings known as the Infinites, an encounter which left him nearly dead. The incident also alerted members of the Avengers, including Moondragon. The Avengers rescued Jack and Moondragon helped restore his armor to his original design with several sophisticated upgrades. Jack and a team of Avengers confronted the Infinites directly, convincing the beings of the danger they posed to the universe. Afterwards, Jack remained alongside the group to confront a galactic federation's decree that Earth should become a penal colony for the universe's known criminals, and he helped expose the alien Kree as masterminds of the plot. Returning to Earth, he helped the Avengers round up the remaining criminals and also helped the Avengers set up new security and analytical tactics to become a more effective team.
Jack remained with the Avengers for several missions, including those against the time-traveling Kang when he nearly succeeded in conquering the Earth. During this time, the Avengers extended membership to Jack in gratitude for his efforts, and he readily accepted. The Avengers also developed a new strain of neutro-mist that allowed Jack to exist safely outside his armor for short periods of time.
Jack appeared to give his life while assisting the Avengers, leaving into space so as to not harm Earth with his explosion of Zero energy. However, his body was apparently reanimated by the Scarlet Witch. 'Jack' returned to the mansion and abruptly exploded, killing Scott Lang and damaging the Mansion grounds.
Jack was later seemingly brought back to life at Project Pegasus using mysterious Z-Energy previously utilized to create a Zombified Squadron Supreme. He was unaware of who or where he was and promptly fainted.
He was subsequently revived by one of Project Pegasus' security officers, Captain Jill Harper and destroyed the zombie Squadron before sharing a kiss with her.