Born a wealthy Italian nobleman, Count Luchino Nefaria grew up regarding himself as one of the rightful masters of the world, and has dedicated his life to making this grandiose self-image a reality. While Nefaria has long devoted himself to the funding and development of exotic new sciences and technologies, he also treasures old-world values, often presenting himself in the manner of a courtly feudal nobleman of ages past. Apparently not content with the power afforded him by wealth and nobility, Nefaria risked his prized respectability and entered the world of organized crime, secretly becoming a leading figure in the international criminal cartel known as the Maggia. With his vast wealth, high-tech resources and natural gift for criminal strategy, Nefaria soon became the leader of his own thriving crime family within the Maggia organization, all the while concealing his criminal connections from the general public.
Luchino wanted a male heir to perpetuate the Nefaria line, but his wife Renata died giving birth to their only child, their daughter Giulietta. Wishing to protect the child from his enemies and hoping to shield her from ever learning of his criminal empire, Nefaria placed her in the custody of Byron Frost, an American financier heavily indebted to Nefaria, and he had Frost raise her as his own adopted daughter, Whitney. While Whitney grew up in America, blissfully unaware of her true parentage, Count Nefaria's Maggia family began expanding their operations into the United States, but they were repeatedly opposed by America's crimefighters, particularly the Avengers. Deciding to handle this obstacle personally, Nefaria had his ancestral castle moved from Italy to New Jersey stone by stone. Opening the castle to public tours and donating the admission money to charity, the seemingly benevolent Nefaria invited the unwitting Avengers to his home, where he trapped them in stasis long enough to frame them for treason by using sophisticated illusions. Reduced to hunted fugitives, the Avengers stormed Nefaria's castle and defeated his mob soldiers, though Wasp was gravely wounded in the process. In the end, the heroes rescued their young Teen Brigade allies from one of Nefaria's death traps, the Avengers were exonerated, and Nefaria was exposed to the world as a criminal.
The Avengers' defeat of Nefaria hurt the influence and stature of Nefaria's Maggia crime family considerably. While he worked to rebuild his empire, Nefaria contacted the now-adult Whitney Frost, revealed he was her father, and invited her to join his Maggia crime family so that he could train her as his future successor. Horrified, Whitney refused the offer at first, but Nefaria threatened to expose her parentage to the world, and her own fiancé abandoned her after he learned the truth about her family. Losing all hope of a normal life, a broken Whitney joined her father's organization, soon becoming his second-in-command. Nefaria, still plotting to destroy the Avengers, targeted Iron Man (secretly Avengers financier Tony Stark) with an illusion-casting "nightmare machine" in an attempt to frighten him literally to death, but Iron Man resisted the device, which a frustrated Nefaria accidentally wrecked. Nefaria next conspired with Tony Stark's ne'er-do-well cousin, Morgan Stark, to ruin Tony's reputation, but this scheme failed as well. Nefaria later shocked the nation by sealing the entire city of Washington under an artificial dome and holding it for ransom, but he and his super-criminal accomplices were defeated by the original X-Men and the city was freed. Nefaria was imprisoned and his daughter took over their Maggia crime family, but the Count soon escaped.
Frozen out of the Maggia due to his very public failures, Nefaria became an independent criminal operator. Employing the Ani-Men (whom he had his scientists mutate into superhumans), Nefaria seized the North American Air Defense Command at Valhalla Mountain in Colorado and threatened to launch America's nuclear arsenal unless he was paid an enormous ransom. His scheme was thwarted by a new team of X-Men, including Thunderbird (James Proudstar), who died trying to prevent Nefaria's escape. His monetary and technological resources dwindling, Nefaria sought superhuman power for himself. Assembling Living Laser, Power Man (Erik Josten) and Whirlwind to battle the Avengers as a new Lethal Legion, Nefaria had their powers boosted by scientist Kenneth Sturdy, but it was a deliberately temporary boost. While the Legion was captured, Sturdy used his process (derived from the ionic energy treatments of Baron Zemo) to give Nefaria the Legion's combined powers, magnified a hundredfold. Despite Nefaria's newly god-like power, the Avengers managed to defeat him after a desperate battle, and the villain learned that he was aging rapidly as a result of the process that gave him his powers.
Deteriorating into an aged invalid who needed a special life-support system, Nefaria escaped custody with the aid of the Ani-Men and his daughter, who by this time had become romantically involved with Tony Stark. When Iron Man (whom Whitney knew to be Stark) tried to take Nefaria back into custody, the Ani-Men and Whitney resisted, and Nefaria was accidentally crushed during the battle. Betrayed by her lover and convinced her father was dead, an increasingly bitter and paranoid Whitney went deep into hiding in her role as crime boss Madame Masque, operating mostly through surrogates for years, even producing clones of herself to act in her stead (one of these "bio-duplicates," a rogue known simply as Masque, broke away from Whitney's service and briefly served as an honorary Avenger before she was recaptured).
Nefaria eventually revived, apparently sharing the regenerative properties common among ionic super-beings; however, he found that he needed to drain ionic energy from others in order to maintain his vitality. Becoming a sort of ionic vampire, Nefaria stalked and drained various ionic-powered beings, killing some of them (notably the Nefaria imitator known as Nefarius) and capturing others (the Deathweb's ionic Therak was imprisoned as an energy source for some time). Trying to cover his tracks, Nefaria was eventually found out and exposed by his old foe Iron Man. Later, Nefaria imprisoned and cloned the inhabitants of the Savage Land for experimental purposes, trying to create a race of ionic beings he could feed off so that he wouldn't have to keep hunting down existing ionics. He was defeated and captured by Captain America and Sharon Carter and left in the custody of the Savage Landers, though he soon escaped. Attacking ionic-powered heroes Atlas and Wonder Man, Nefaria absorbed some of their energy and realized that this process enabled him to subjugate their wills, too.
Aided by his new slaves, Nefaria sought to consolidate the Maggia crime families under his leadership (with the Grim Reaper acting as his lieutenant) and tried to force Whitney to return to his service, all as part of a larger scheme to mutate the entire world with ionic radiation so that everyone would be compelled to obey Nefaria. His plot was thwarted through the combined efforts of Whitney, the Avengers and the Thunderbolts, though not before Nefaria murdered the heroic bio-duplicate Masque, whom he believed to be his rebellious daughter. In the end, Nefaria was apparently blown to atoms, but he somehow survived and was jailed in the super-prison known as The Raft, where he was recently among the many inmates who escaped during a prison break sparked by Electro.