BIOGRAPHY - Page 10
Although Quicksilver found new peace with his daughter and with the X-Factor team, his past actions continued to return to haunt him. Wanda accidentally let his deal with Havok slip to Lorna during a sisters' night out. [All-New X-Factor #14] Polaris was seriously upset at Quicksilver for spying on her, and Pietro had little to defend his actions with. He admitted he made a mistake and pled only that he had ultimately chosen X-Factor over the Avengers. Still, the trust that had grown between the... siblings... was broken. [All-New X-Factor #16]
They had little time to deal with hurt feelings as World War Hate broke out around the world. The Red Onslaught had combined the brain of Charles Xavier with the Nazi hatred of the Red Skull, telepathically producing a wave of hatred that consumed the world. The Avengers and X-Men confronted the creature on Genosha while X-Factor (psionically shielded by tech provided by Warlock), tried to hold the world together in the meantime, including confiscating the “nuclear football” before the President of the United States used it to finally tell Russia how he really felt. [All-New X-Factor #15-17]
The Red Onslaught was stopped by an Inversion spell of chaos and order cast by Wanda and Doctor Strange but, in the process, many of the heroes and villains on Genosha had their base 
natures inverted. Wanda turned towards insanity again as the dark Scarlet Witch, and Magneto recruited Pietro to confront his sister and prevent her from doing anything she would regret later. Quicksilver and Magneto opposed Wanda in Latveria as she tried to murder Doctor Doom for his involvement in her last meltdown. Wanda grew enraged during the fight and cast a spell designed to attack her family and strike down those of her bloodline. Miraculously, while Quicksilver was injured by her spell... Magneto remained completely unaffected! From this incantation, the twins learned that their years believing Magneto was their father were a lie, leaving their true parentage a mystery. [Avengers & X-Men: Axis #6-8]
The revelation that Magneto was not his father (and, therefore, Polaris was not his half-sister) further strained Quicksilver's relationship with X-Factor. He chose not to accompany the team on one of their missions and, ultimately, tendered his resignation to Lorna via video message before they returned. [All-New X-Factor #18-20]
Instead, Quicksilver returned to the Avengers and became part of the Unity Squad alongside Wanda. Seeking answers about their true parentage, the twins traveled to their birthplace on Mount Wundagore, hoping to consult with the High Evolutionary. There they were drawn through a portal to Counter-Earth, once again populated by New Men on the other side of the sun. The Evolutionary was in one of his more manic and self-aggrandizing phases, creating entire populated cities before wiping them out once he was convinced they were not yet perfect. [Uncanny Avengers (2nd series) #1]
Quicksilver and the Scarlet Witch found themselves allied with the "Low Evolutionary," a previous 
creation of the High Evolutionary's who had been deemed unfit but survived his "father's" cullings to create an underground. They learned that their abilities were not those of true mutants, but were genetically engineered in them as infants by the High Evolutionary as one of his various experiments. He had even progressed further with those experiments to create Luminous, a being with heightened speed and chaos control powers. Pietro had been thrilled to cast off the legacy of Magneto, but he and Wanda began questioning whether the Evolutionary was their real father. After capturing them, the High Evolutionary scoffed and dismissed the idea. They were not the long lost prince and princess of his kingdom, he said... merely another failed experiment made from children taken into his care. The Avengers Unity Squad reunited in time to flee Counter-Earth and return home, with the twins only marginally more informed about their origins. [Uncanny Avengers (2nd series) #2-5]
Pietro took a lesson from the High Evolutionary's mistreatment of them and chose to just move on. While Wanda left the Unity Squad and continued to explore their roots, Pietro was comfortable 
with just NOT being Magneto's son anymore, and ignored any further investigations into their past. He became more carefree and sociable, even dating again using his speed to court multiple women in different countries on the same evening. Quicksilver was still cocky and impulsive, however. He confronted an Inhuman opponent named the Shredded Man in Boston without waiting for his teammates, and was temporarily killed. Only the power of Doctor Voodoo prevented Pietro's soul from remaining on the other side of life and death. [Uncanny Avengers (3rd series) #1-4]
With the Avengers fallen on hard times, Avengers Mansion had to be sold for funding, and it was turned into a tourist hotel. On a return visit, Quicksilver and Deadpool decided to check on the sealed catacombs. Unbeknownst to Deadpool, Pietro encountered the Red Skull hiding in the catacombs, who used the stolen telepathic brain of Charles Xavier to plant a suggestion in his subconscious. This allowed the Skull to use Pietro to his advantage without him even knowing it. [Uncanny Avengers (3rd series) #6]
Quicksilver's arrogance cost him dearly when the Avengers confronted a newly-returned Ultron, who had forcibly merged with his father, Hank Pym, to create an even more powerful killer robot. 
Pietro rushed in to strike at Ultron without backup, but Ultron's reflexes were fast enough to grab Quicksilver in mid stride, snapping the bones in his leg. Pietro was hospitalized for some time, although his own rapid healing was supplemented by Synapse's neural tweaking. [Uncanny Avengers (3rd series) #11,14]
A rift had grown between Pietro and Wanda ever since she left the Unity Division. Pietro had grown impatient with their quest for answers about their past and moved on from ever wanting to deal with their roots, preferring to live in the present. When the Ulysses Initiative drew battle lines between Iron Man and Captain Marvel, Pietro rushed to Wanda's apartment to recruit her for the struggle. Barely willing to slow down enough to lay out the situation for her, Quicksilver tried to drag his sister into the conflict with a promise to explain things better later. However, the Scarlet Witch would not be led around by her brother anymore. She had discovered the identity of their true mother, but Pietro was just as disinterested in her quest as she was in his Civil War. Old resentments boiled up as Wanda confronted Pietro with everything from being overprotective of her as children to instigating her actions during the House of M. The twins lashed out at each other, physically and verbally, and Quicksilver left empty-handed, with the two of them further apart than they had ever been before. [Scarlet Witch (2nd series) #9]
The emotion turmoil of his separation from his sister made Pietro only more vulnerable to the Red Skull's influence. The Skull telepathically imposed his will on Quicksilver, breaking his spirit with thoughts about separating from his sister, his failures as a husband and father, losing his identity 
as a mutant, etc. He also confronted Quicksilver with his feelings about his teammate Emily (Synapse), which Pietro had yet to acknowledge or act upon himself. With Quicksilver under his power, the Red Skull surprised, gathered and incapacitated the rest of the Unity Squad at Avengers Mansion, turning them into his puppets against Deadpool, whose mind was proof against telepathic intrusion. Only when Deadpool retrieved Magneto's psi-proof helmet and slapped it on Rogue did the tide turn. The Red Skull was defeated and the telepathic grey matter of Xavier's brain was finally removed. [Uncanny Avengers (3rd series) #18-22]
Pietro and Wanda managed to reconcile on her long quest to cure the ailment affecting witchcraft. Wanda had located the spirit of Natalya Maximoff, their birth mother, and joined forces with her and Agatha Harkness against the essence of Chaos attacking witchcraft. Natalya summoned Quicksilver to the Witches' Road to provide a boost of kinetic energy they needed to complete their spell as the Witches Three. Pietro and Wanda immediately apologized to each other for their earlier spat, and Pietro had a brief moment to greet his mother before being pulled back to the material world. [Scarlet Witch (2nd series) #14]
Still, Quicksilver soon experienced one of his reoccuring nightmares again when the dimensionally-displaced Captain America loyal to Hydra took over the country. As part of his vast plot, he arranged for Wanda to be possessed by an aspect of Chthon again. Synapse, Rogue, and most of the Unity Division were trapped behind a Darkforce barrier in New York, leaving Pietro and a rag-tag underground of heroes fighting against Hydra's America. As he had in the past, Quicksilver became obsessive about his sister's wellbeing, blaming himself for failing her yet again. [Secret Empire crossover]
Pietro was still reeling in the aftermath of the takeover when Wanda (freed from Chthon through no effort of Pietro's) wanted to join the group again. Quicksilver had difficulty reconciling his guilt over failing his sister with the horrors he saw her unleash under Chthon's influence. He was also preparing to finally express his feelings for Emily, but Rogue called a meeting of the Unity Division just as he was finding the words.
Even more impatient than usual, Quicksilver was in no mood to follow orders for crowd control when the Avengers found themselves facing Juggernaut. In order to show off for Emily and demonstrate his own prowess, Quicksilver charged headfirst into the fray. His plan was simply to remove Juggernaut's helmet and allow Synapse's mental powers to bring down Cain Marko, as he had fallen so many times before. In his arrogance, however, Pietro neglected to realize Juggernaut wore a second protective helmet under the first, leaving Emily helpless in 
Juggernaut's path. It fell on Wanda and Doctor Voodoo to dispatch Juggernaut while Synapse paid the price for Quicksilver's mistakes.
At the hospital later, Emily was announced to be in stable condition. Pietro's guilt made him even more insufferable than ever as he tried to deny responsibility, tried to assert his value as a senior Avenger, tried to drag Wanda into his antics, and so on. Wanda finally denounced him, telling Pietro he needed to leave until he was willing to own up to his mistakes. Quicksilver regretfully recognized the truth when he heard it. By the time Emily woke up, Pietro was gone from the Avengers. He left her a note that did nothing to confess his true feelings, but only asked her forgiveness. Whether Quicksilver will truly learn patience and humility in his time away is anyone's guess. [Uncanny Avengers (3rd series) #26-30]