Eager to prove himself to Magneto since he was a child, Pietro joined his Brotherhood. Pietro was always abused by his father however, leading him to greatly resent and eventually betray him. When Magneto attacked Washington, D.C., with a fleet of reprogrammed Sentinel robots, it was Pietro who surreptitiously removed his father's thought-proof helmet -- enabling the telepathic Xavier to transform his one-time friend into a living super-magnet.
Pietro and Wanda defected from the Brotherhood and opted to join the Ultimates for amnesty. Together, they aided the team on a few missions, including the invasion of America by the Liberators. During the battle, Pietro saved Hawkeye's life when he was being attacked by the Liberator speedster, Hurricane. Pietro managed to take Hurricane up to speeds far faster than she had been trained to go, literally ripping her body apart at a molecular level, stating that he'd already been able to reach Mach-10 when he was just a teenager.
A short while later, Wanda was murdered by Ultron, an android created by Hank Pym that gained sentience and became infatuated with her, when he realized he could not be with her romantically. Pietro, devastated by his sister's death, returned to his father's side. He was later apparently mortally injured while protecting Magneto.
When Moira MacTaggert was left to die in an exploding building by Wolverine, Pietro rescued her, revealing that he was in fact alive. He informed her that his father had a plan to deal with the humans.
He later resurfaced during Scott Summers' mutant rights speech. Pietro assassinated him by lodging a bullet into his skull; presumably the same bullet used to kill his sister. Pietro later talked to Moira, holding his father's helmet, stating he would carry on Magneto's legacy.
Following the deaths of a large part the X-Men and the Brotherhood, both Jean Grey (now "Karen Grant") and Pietro started a search for new members of the respective teams. Mystique, Sabretooth and Teddy (the son of Blob) joined him, along with a seemingly reborn Wanda.
Pietro appeared again to arrange a meeting with the Chief Executive of World Wide Solutions Inc. to gather mutants and sell them to the company to use their powers as gathered services. During a romantic liaison with the Chief Executive's assistant who granted him the meeting, the projection of Wanda appeared and he revealed he was following her orders and she requested that he travel to Egypt for further truth.
Wanda tells Pietro to go to Egypt, saying he would find something "special" there. Following his sister's orders, Quicksilver tried to manipulate the White House, inadvertently resulting in the death of many mutants at the hands of Nimrod Model Sentinels, which were controlled by the Reverend Stryker before his death. Desperate, he went to his hideout, blaming his sister. She told him that she was following the orders of another. When Pietro finally followed her advice and went to Egypt, he found his father, Magneto, still alive.
After researching the Mothervine, a concoction that when injected would ensure that a pregnant mother gave birth to a mutant that could be programmed and used as a weapon, Pietro attempted to use it to save the mutant race. While researching Mothervine he discovered that his mother hadn't died when he was a child as his father had told him, and that he had a half-brother; Jimmy Hudson who carried the original Mothervine strain in his blood. Pietro attempted to gain his brother's aid, but appalled at Pietro's methods, Jimmy lashed out at him. The two began a fight to the death that was interrupted by Pietro's mother Magda, who knocked out both her sons. She arranged for Pietro's medical care before disappearing once more. 
Pietro was recruited by the mysterious woman known as Kang to form a new version of the Ultimates, with the objective of collecting the remaining Infinity Gems after the ones found by S.H.I.E.L.D. were stolen from them by Hulk and The Maker, both also recruited by Kang.
After retrieving the final gem, Pietro used his super-speed to spy on Kang's calculations, whom he believed to be his sister Wanda, and discovered she planned to erase the mutant gene as soon as she used the complete Infinity Gauntlet to rebuild the world. Pietro ran away, but was found by Kang, who decided to kill him in order to get the gem from him. Pietro survived, but as soon as he realized his metabolism wouldn't be able to heal his wounds, he used his last seconds of life in order to go to Wanda's grave in the Black Forest and confess before it.
The Final Incursion and New Marauders
Pietro later appeared to have been somehow brought back to life. He witnessed an instance of the cosmic phenomenon known as an incursion, the one which caused a collision between the planet Earth of his universe and that of an alternate reality, Earth-616, that resulted in the destruction of both universes. In the final moments of this incursion, when both universe's Earths were in very close proximity, Pietro and a group of mutants, namely Jimmy Hudson, Mach Two, Guardian and Armor, fell from their reality into Earth-616. When the Multiverse was eventually rebuilt, Quicksilver and these mutants became stranded in the Prime Earth, suffering from amnesia as a by-product of their transition from one reality to another.
Pietro and the other foreign mutants were abducted by super-villain geneticist Miss Sinister, who brainwashed and turned them into her personal enforcers, the New Marauders. When Jimmy's natural resistance to telepathy allowed him to break free from Ms. Sinister's control and he went rogue, the New Marauders were deployed to retrieve him. In the process, they confronted the young X-Men, who had tracked down Jimmy after he was detected by Cerebro. Following a brief confrontation against the X-Men and Jimmy, during which Marvel Girl learned of Miss Sinister's involvement, the New Marauders were ordered by their superior to leave.
Ms. Sinister continued experimenting on Quicksilver and the other mutants, granting them secondary mutations through a method called the "Mothervine." However, not all attempts were successful, with one of them resulting in Quicksilver's death. Pietro's body was left behind by Ms. Sinister in her base once she abandoned it, and it was eventually found by the young X-Men while investigating.
Superhuman Speed: Quicksilver is able to think and move at extreme speeds. He is fast enough to run across the U.S.A in a matter of minutes. His entire body has adapted to the rigors of high-speed running, and his cardiovascular and respiratory systems are many times more efficient than those of a normal human being. His body can somehow resist the immense friction generated by high speed movement to a degree unmatched even by other Ultimate Marvel speedsters. Quicksilver has stated he can run at speeds up to Mach 10 even as a teenager. The longer he runs the more momentum he gains and the faster he becomes. He is so fast, that he was able to casually reach speeds near light  and create miniature sonic booms by snapping his fingers or clapping his hands. He can even create a vibrational field to shield him from the sight of security cameras and nearby witnesses. Also, his metabolism is augmented to the point where he could heal from minor wounds.
Bilingual: Quicksilver is fluent in English and German.
- 79 appearance(s) of Pietro Lensherr (Earth-1610)
- 1 appearance(s) in handbook(s) of Pietro Lensherr (Earth-1610)
- 3 minor appearance(s) of Pietro Lensherr (Earth-1610)
- 7 mention(s) of Pietro Lensherr (Earth-1610)
- 1 mention(s) in handbook(s) of Pietro Lensherr (Earth-1610)
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- 4 quotation(s) by or about Pietro Lensherr (Earth-1610)
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