- "I have been planning to destroy the Breakworld since I was a child... (awkward pause) ... This is why I don't make so many jokes. I never know when is good."
Piotr "Peter" Rasputin was born on a Soviet collective farm called the Ust-Ordynski Collective near Lake Baikal in Siberia. He lived there with his mother Alexandra, father Nikolai, and sister, Illyana. His older brother, Mikhail, had been a Russian cosmonaut and had apparently died in a rocket accident. Peter's superhuman powers manifested during his adolescence while saving his sister from a runaway tractor. At first, Peter was content simply to use these powers to aid the other people of the collective; however he was soon contacted by Professor Charles Xavier, the founder of the X-Men. Xavier was recruiting a new team of X-Men to rescue the original team, most of whom had been captured by the sentient mutant island Krakoa.
Joining the X-Men
Peter was part of the second generation of X-Men, formed by Charles Xavier to save the original X-Men from the living island Krakoa. He agreed to leave the farm community in which he was born to go to the United States with Xavier. Xavier gave him the name "Colossus." After the battle was won, Colossus remained in the United States with the new X-Men. Colossus is typically portrayed as being peaceful, selfless, reluctant to hurt or kill anyone, and always putting himself in danger to protect others. When the X-Men storm Hell to save Nightcrawler, Colossus pries open the gates of the city Dis and the demons flee in front of him. Doctor Strange remarks, "...according to Dante, only one figure could open these unholy gates by force". However, this version of Hell is later shown to be an illusionary construct, and not the actual Hell. In some of his earliest missions, he first battled the Shi'ar Imperial Guard, and first visited the Savage Land, where he met Nereel. Peter's family always remained in his thoughts and he frequently wrote letters home.
Shortly after joining the X-Men, a woman known as Miss Locke kidnapped many of the team's loved ones to use as hostages in order to force the X-Men to aid her in freeing her employer, Arcade, from captivity by one of Doctor Doom's robots. Among her captives was Colossus' younger sister Illyana, whom Locke had kidnapped from the Siberian collective farm and transported to the United States. Arcade brainwashed Colossus into becoming "The Proletarian," and he battled the other X-Men until they countered the brainwashing. The X-Men freed Illyana from captivity, and she went to live with her brother Peter at Xavier's mansion. Due to her later captivity in a dimension known as Limbo where she spent years while only mere moments elapsed on Earth, Illyana became the adolescent sorceress known as Magik. When the X-Men fought the Proteus, Colossus thought he had killed Proteus on coming into contact with his metal skin. During his early career with the X-Men, Peter started what was arguably his most significant relationship with fellow X-Man Shadowcat.
Although they were only together as a couple for a short while, the relationship provided the foundation of a deep and lasting friendship. During the Dark Phoenix Saga, Colossus was forced to battle the Dark Phoenix. He punched the Dark Phoenix, temporarily stopping the Phoenix so that Cyclops could kill her. He then battled the Imperial Guard again, in an attempt to save Phoenix's life. Colossus was later turned into unliving metal, but was returned to normalcy by the Morlock Healer. During the Secret Wars, he became infatuated with the alien healer Zsaji, and realized his feelings for his teammate were not wholly genuine, ending his relationship with Kitty Pryde. He then battled the Juggernaut one-on-one.
During the Mutant Massacre, Colossus became heavily involved in the X-Men's efforts to save the Morlocks from the Marauders. When Kitty was severely injured by Harpoon, Peter gave in to his rage and snapped Riptide's neck. He tried to fight through his pain and anger, but eventually passed out from previous wounds inflicted by Riptide. Magneto, with the aid of Shadowcat, used his powers to heal Peter's armored form, but the process left him paralyzed. He was sent to Muir Island along with Nightcrawler, Shadowcat, and the surviving Morlocks to recuperate. Over time, Colossus' wounds healed, but he could only retain his human form with the utmost concentration. When he saw the X-Men in Dallas during the Fall of the Mutants, he had his sister teleport him to the battle, where he became a wild card, as Destiny had not seen him in her vision of the X-Men's demise. When the team decided to sacrifice themselves to stop the Adversary, Colossus went along, dying to save the world. Like the rest of the X-Men, he was revived by Roma and decided to let the world believe him dead while he and the X-Men worked out of an Australian base.
Following the Inferno event, Illyana was returned to her original Earth age. Colossus decided it would be better for Illyana if she went back to live with their parents in Russia. In time, Colossus was reunited with Nereel in the Savage Land, and met her son. He battled the Cold Warriors during this period. After the X-Men began falling apart with Rogue vanishing, Wolverine taking off, Longshot quitting, and Storm apparently killed, Psylocke telepathically prodded the remaining three to disband and travel through the Siege Perilous to gain new lives. Peter emerged in New York with no memory of his past life, inventing a new persona for himself as 'Peter Nicholas', where he quickly became a successful artist. He battled the Genoshan Magistrates. He began having visions of a beautiful model, who turned out to be Callisto transformed by Masque. The two were kidnapped by the Morlocks, though Peter had no memory of his time with the X-Men. He resumed his armored form and defeated Masque. He was saved by Forge, Banshee, and Jean Grey, who decided it better that he live his new life rather than be dragged back into theirs.
Unfortunately, Peter was psychically dominated by the Shadow King and sent to hunt down Stevie Hunter and Charles Xavier. Xavier had no choice but to destroy the Peter Nicholas persona to break the Shadow King's hold. Colossus joined in the battle of the Muir Island Saga, and rejoined the X-Men as a member of Storm's Gold Strike Force. Not long after, Peter's parents were slain and Illyana kidnapped by the Russian government, who hoped to genetically evolve Illyana to the point where she would have the use of her powers again, to defeat the mutant known as the Soul Skinner. Colossus, with the help of the X-Men, saved Illyana and brought her back to the Mansion. The X-Men later found themselves in another dimension where they discovered Colossus' brother, Mikhail, was alive and acting as a messiah to the population of that world. Mikhail returned to Earth with the X-Men, but was distraught with having been responsible for the deaths of the original crew from his first trek into the other dimension. Mikhail established himself as leader of the Morlocks and transported them to another world. Peter was disappointed by his brother's abrupt departure and blamed himself.
Later, Illyana became an early victim of the Legacy Virus and died from it. The loss of his immediate family, as well as brain damage that forced him to remain in armored form, caused Colossus to rethink his position with the X-Men and join Magneto and his Acolytes, who had offered him an alternative to the X-Men's pacifist philosophy of peaceful mutant/human coexistence. Colossus would eventually recover from the brain damage, but decided to remain with the Acolytes of his own volition, hoping he could temper the Acolytes' extremist methods with what he had learned from Professor Xavier.
His stay with Magneto was not long once he realized that Avalon was not the place for him, either, particularly after Magneto was left brain-dead and the space station was destroyed by Holocaust. He left in search of the only person he felt truly cared for him, his former love and teammate Shadowcat, now a member of Excalibur. Colossus traveled to England, where he found Kitty in the arms of her new love, Pete Wisdom. Colossus, exhausted, mentally ill, and enraged, attacked Wisdom, and although the battle was short, Peter nearly killed him. Colossus was subdued by Capt. Britain and Meggan, later cured of his illness by Moira MacTaggert. Colossus accepted Shadowcat's new life and chose to become a member of Excalibur.
Although Colossus, along with the rest of the team, soon accepted Kitty's relationship with Wisdom, Kitty's pet dragon, Lockheed, did not, and was often seen trying to reunite Kitty with Peter who he much preferred. One such example being snatching away the garter during Meggan and Captain Britain's wedding and dropping it into Colossus' hand, who was then required to place it on Kitty's leg, who had previously caught the bride's flowers. With Excalibur, he participated in many adventures, including helping to save London from an ancient demon. Excalibur eventually disbanded, and Colossus returned with Nightcrawler and Shadowcat to the X-Men.
But as soon as they returned, they faced a group of imposters following Cerebro, in the guise of Professor X. During this time, he repaired his friendships with Wolverine and Storm, that were broken when he had joined the Acolytes. He created a deep friendship with Marrow. Peter again found his long thought-dead brother Mikhail, but unfortunately lost him again when Apocalypse collected The Twelve in his quest for power.
Using thoughts and notes from the recently murdered Moira MacTaggert, the X-Men's resident scientist, Beast, claimed to have found the cure for the Legacy Virus. Unfortunately, it could only be made airborne with the death of its first user. Rather than wait for a safer version and allow others to die as Illyana had, Colossus injected himself with the cure. By using his powers and sacrificing himself, Colossus enabled the release of an airborne cure, effectively eradicating the disease. His body was cremated, and Shadowcat took his ashes back to Russia to be strewn on his native soil.
Nearly 2 years later, it was brought to the attention of the X-Men that a medical company, entitled Benetech, had developed a mutant cure. After gaining a sample of the cure, Dr. McCoy discovered a string of DNA hidden deep within the recesses of the formula. After matching the DNA, Beast and the other X-Men set out to investigate the truth behind Benetech. During their infiltration, they discovered that Ord, an alien from the Breakworld, was responsible for the means with which the company was able to develop the cure. While the team was separated, Kitty descended into a hidden complex beneath the Benetech building and was able to unlock the true secret behind the cure: shortly after Peter's self-sacrificing death, Ord had captured his body and left a duplicate that the X-Men had cremated.
After reviving him, Ord had used the Legacy Virus cure in Peter's blood stream to develop his mutant cure. After unknowingly releasing Peter from his cell, Kitty rejoined him with the X-Men and together they subdued Ord as he tried to escape Earth. Since reuniting with his friends, Peter has returned to fight with the X-Men, and he and Kitty were able to resume their romantic relationship.
During the Colossus: Bloodline mega-series, Colossus made a trip to Russia in response to a call for help from his cousin, journalist Larisa Mishchenko. Her research had established that their family descended from Grigori Rasputin, and that their relatives were being systematically murdered. Rasputin is established as having been a powerful mutant, whose power and life essence had been passed down to his descendants. As his descendants are murdered, his great power is invested in greater measure in the remaining descendants. When there is only one descendant left, Rasputin will be re-born within that individual. Mister Sinister, an old ally of Rasputin, is revealed as the man behind the murders. Larisa is murdered by Sinister, but Colossus and his brother Mikhail foil Sinister's plot, and Mikhail banishes himself to a dimension where he can never die, but from which he can never return.
If Sinister were to murder Colossus, Rasputin would be re-born in Mikhail, but locked in a dimension on his own. However, all those involved remained unaware of Colossus' son, Peter, in the Savage Land, whose presence could severely alter the situation. Colossus returned to the X-Men, a man without family. It is rumored that the boy Michael Termani escaped the extermination and made his way to the United States of America in search of Colossus, whom he may be related to.
During an attack on the institute, Colossus engages Sebastian Shaw, although "Shaw" turned out to be an illusory attack by Cassandra Nova. It was revealed that Colossus is the mutant destined to destroy Breakworld according to the Breakworld's precogs. However, on a mission to the Breakworld, the X-Men discover that this was not an actual prophecy but an elaborate scheme created by Aghanne, the insane leader of a Breakworld reform cult, intended to bring about that world's destruction. Colossus is chosen for the prophecy as his unique organic steel form would allow him to destroy the planet's power source, initiating a chain reaction that would destroy the entire world. Realizing this, Colossus refuses to kill the planet although he does threaten to seize power and rule it if the Breakworld destroys the Earth as planned.
World War Hulk
Colossus is one of the X-Men members that tries to defend Professor Xavier against the Hulk, who has come looking for Charles as he is one of the members of the secret Illuminati that exiled him from Earth. They battle in issue #2, with the Hulk commenting on Colossus' bravery and mentioning that Colossus might have made a "decent opponent" to the Hulk's previous incarnations, before breaking his arms.
Colossus was with Wolverine, Angel, Storm and Nightcrawler when it came to hunting down some Acolytes in their search for Exodus. He was involved in a battle with The Marauders. During the fight, he faced off against Frenzy, Unuscione, Arclight and a Malice possessed Omega Sentinel all at once.
Divided We Stand
Colossus returns to Russia with Wolverine and Nightcrawler along for the ride. The trio are captured by the Russian government, who wish to find out why all their mutant agents succumbed to M-Day, and Colossus did not. This led to a battle against the Russians and Omega Red, who was being examined by their captors. After defeating Omega Red, the boys received a call from Cyclops informing them of their new home in San Francisco. Soon, they arrive back in the States, where they aid in rebuilding the X-Men.
The Last Defenders
Colossus was briefly a member of the Fifty State Initiative team called The Last Defenders alongside Nighthawk, She-Hulk and Blazing Skull.
Joining the rest of the X-Men, Colossus relocates to San Francisco. Still mourning Kitty, the other X-Men try to cheer him up using various different methods from picking fights with him to throwing a party. In the end he tells them to leave him be, he just needs time. Later while walking through Golden Gate Park, he come across a little girl who needs help rescuing her Kitty from a tree to which he replies that nothing would make him happier.
Colossus is seen working alongside Cannonball and Armor when the Skrulls invade San Francisco. He later saves Anole when he doesn't get to his rendezvous point.
Colossus is wondering why the X-Men are doing nothing to save Illyana from Limbo. Scott says they've tried and will keep trying but Limbo is still currently sealed off. Amanda Sefton has been unable to break the seal, Doctor Strange is nowhere to be found and Warren has scientists looking into it but this is magic and there is nothing more they can do. Colossus says he doesn't accept it. After Magik reclaims her Soulsword, Colossus finds her and after he calls her 'Snowflake' to which she responds by striking him. Illyana feels something is wrong when she doesn't feel any emotion and teleports back to Limbo telling her brother he can't save her, she has to save herself.
The X-Men gather, now with a way to enter Limbo through Pixie. The group forms a team consisting of Colossus, Pixie, Wolverine, Mercury and Rockslide with Kurt in charge to maintain objectivity due to Pixie and Peter's personal stake in the mission. The team teleports to Limbo, encountering many hostile demons. The team fights through an army of demons, with Colossus attacking them with severe brutality, horrifying the younger members on the team. Pixie suddenly teleports alone to Belasco's castle, sensing a growing darkness in her soul. The team follows, finding Illyana defeated by Witchfire, who turns Wolverine and Colossus against the others. Colossus incapacitates Mercury, becoming demonic in appearance.
The only member of the team left undamaged is Nightcrawler, who using both Magik's Soul Sword and Pixie's Soul Dagger, frees Logan and Colossus of Witchfire's control. Together the X-Men and Magik defeat Witchfire, by trapping her in the dimension that houses the Elder Gods. Their actions result in the Bloodstone Amulet containing pieces of Illyana and Megan's souls being trapped with Witchfire. While Pixie flees, Colossus and Nightcrawler try to coax Illyana into returning with them. At first Illyana refuses, believing herself too monstrous to be around them. Cyclops however steps forth to remind her that they are all her family. He and Peter offer her a home, which she accepts.
When the Dark Avengers head into San Francisco to battle any X-Men they can find, Colossus battles Venom. They later face off again when the combined Dark Avengers and Dark X-Men attack Utopia, with Colossus and the X-Men emerging victorious. Fear Itself When the Juggernaut - now possessed by an ancient Asgardian spirit in the service of the Serpent, ancient Asgardian God of Fear and true heir to the position of All Father - came to San Francisco, the X-Men attempted to stop him at all cost, despite the Juggernaut offering them amnesty if they killed the humans of San Francisco. All their plans failed to stop the Juggernaut so Cyclops sent Magik, Colossus and Kitty Pryde to confront Cyttorak, the demon that gives the Juggernaut his power. Magik told Cyttorak that the Juggernaut was serving another god which enraged Cyttorak and made him withdraw his blessing from Cain (the Juggernaut). Magik offered to become his new avatar, but Colossus intercepted, refusing to let his sister carry this burden. Colossus became the new Juggernaut, and with his increased power he was able to drive Cain back. Schism
During the events of Schism, Shadowcat argues with Colossus that he belongs at Westchester Academy, not at Utopia. Colossus explains that he is not remaining on Utopia out of obligation to his sister, Magik, rather he is scared of his power and what harm he could do to the students at the Academy. A tearful Shadowcat tells him that if he needs anything, he must call her.
Avengers Vs X-Men
Colossus is there when Utopia is invaded by the Avengers, and goes toe to toe with Spiderman and The Thing in battle. When the conflict moves to the moon, he goes with the X-Men. When the Phoenix Force is split into pieces, Colossus is one of the X-Men that the Phoneix Force takes possession on. Colossus and his fellow Phoenixes use their power to make the Earth a better place, providing free water, food and energy to everyone in the world.
He approaches Cyttorak and asks to be dismissed as his avatar since he now serves the Phoenix. Cyttorak refuses however and tells Colossus that he is his favorite avatar in millennia since as a hero he engages in violent and destructive battles on a regular basis and that he is willing to share him with the Phoenix, with whom he's not completely incompatible. Colossus attempts to use the Phoenix powers to force Cyttorak to release him but Cyttorak merely dismisses him and sends him back to Earth.
The Avengers still mistrust the X-Men and their new powers and fight a guerrilla war against the X-Men. They manage to take out Namor, causing his portion of the Phoenix to go to the others. This increased power proves even more for them to control and Colossus begins to lose touch with reality. During a fight with the Avengers, his sister eggs him on to kill Spider-Man when Colossus refuses to injure him too seriously. Colossus becomes disturbed by what his sister is saying and suggests that perhaps he should carry the burden of her portion of the Phoenix. This leads to an argument between them and after being egged on by Spider-Man, the two battle and take each other out, causing their portions of the Phoenix to go to Emma and Cyclops.
After being released from the control of the Phoenix, Colossus laments all that he has done and declares that he is finally damned. Magik responds with "finally" and explains to him that she manipulated him into becoming Cyttorak's avatar to corrupt him so that he would understand what it felt like to be damned like her. Colossus lost control of himself and tried to kill her but she merely teleported him away and left.
Colossus made his way to the Siberian farms he had created as a Phoenix and was once again approached by Magik. He transformed again and tried to kill her but Magik teleported him to Limbo and using her soulsword, severed Cyttorak's connection to him. She explains that every Hell Lord is the master of his domain and as MIstress of Limbo, her soulsword was strong enough to sever Cyttorak's hold while in Limbo. Colossus, realizing that Magik could have done this at any time she pleased tells her that if he sees her again he will kill her.
Rid of his status as Avatar of Cyttorak, yet still tormented by his actions as an Avatar and a Phoenix, Colossus vowed to give up being a superhero and retreated to a cave in Siberia to think about his next move. Magik told Magneto where he was, and finding him damaged, he contacted Storm, since he trusted her to do what was best for Colossus. Storm attempted to bring Colossus in with her, but he refused. Unwilling to turn in her friend, Storm left, with a final warning to kill Magik from Colossus.
Broken Powers and X-Force
After some time, Colossus began to lose control of his powers, being unable to maintain his iron or flesh form, and being stuck in a halfway state. He went to New York where he was given shelter by a friend. He was approached by Cable who had assembled a new X-Force team to perform a final mission. Cable assisted Colossus with his powers, giving him a device that would enable him to once again control his transformations, in exchange for help in his final mission.
Powers and Abilities
Organic Steel Transformation: Colossus is a mutant with the superhuman ability to convert the tissues of his entire body into an organic, steel-like substance. This substance resembling steel is of unknown composition, but appears to be analogous to osmium and carbon steel. He is able to transform into this armor-like state at will (the process is virtually instantaneous) and remain in that form for an as-yet undetermined amount of time. (The longest time he has remained in armored form by choice so far has been five days). Once in his armored form, he remains so until he consciously wills himself back to normal. If he is rendered unconscious, however, he spontaneously reverts to his normal form. While in the armored state, Colossus possesses the same degree of mobility that he does in his normal form. The conversion from flesh and bone to organic steel is accomplished by a psionic whole-brain interface with an ionic form of osmium, an extremely dense metal, located in another dimension. In willing the act of transformation, Colossus actually exchanges osmium atoms for his carbon atoms. The psionic interface with the other dimension re-creates all of Colossus's body in functionally-similar organic ionic-osmium materials. The process by which Colossus gains additional mass from an unknown, perhaps extra-dimensional, force remains unknown. Colossus cannot become partially or selectively armored; his whole body is either entirely converted or not.
- Superhuman Strength: After transforming into his armored state, Colossus possesses vast superhuman strength. As a teenager, he was sufficiently strong enough to lift about 70 tons. However, as a fully mature adult, his strength has increased, though the exact amount he can lift isn't clear. It is known that he is able to lift at least 70 tons.
- Superhuman Stamina: Also, while in armored form, Colossus' musculature produces considerably less fatigue toxins than the musculature of a normal human. At his peak, he can physically exert himself at peak capacity for several days before the build-up of fatigue toxins in his blood begins to impair him.
- Superhuman Durability: In his armored form, Colossus is invulnerable to most forms of bodily harm. His armor is capable of withstanding ballistic penetration, including that of a 110 millimeter Howitzer shell. He can survive extremes of temperature from 70 degrees above absolute zero (-390 degrees Fahrenheit) to over 9000 degrees Fahrenheit. He could survive a collision with a loaded, one-ton flatbed truck at 100 miles per hour or an explosion of 450 pounds of TNT. He does not need to breathe while transformed, but it is believed that he could not survive for long in a vacuum. Colossus' body attracts electricity like normal metal but he is actually immune to the effects of it himself. He can also survive falls from great heights while in his armored body. Colossus tends to jump at foes from a height creating a shock wave when he lands, due to his armored form. He can go without food, water, or air for many days while transformed, though he would eventually require sustenance.
Skilled Painter: Peter is a highly skilled artist, once becoming very famous using the name Peter Nicholas while suffering from amnesia.
Expert Combatant: Even though Peter has a gentle demeanor and personality, he is a dangerous hand-to-hand combatant, having received some training personally from Cyclops. He has also honed himself through years of combat training within the X-Men's Danger Room.
Class 100 strength. Currently, Piotr is strong enough to lift at least 100 tons. As a teenager, he was not as strong and could lift about 70 tons. Also, even without transforming into his metal form, Piotr possesses the strength of a human of similar age and build who engages in regular, extensive exercise. As a result, he can lift up to twice his body weight. Piotr can press lift 700 lbs in his normal form.
Magnetization: Due to the fact that Colossus' skin in his metal form acts like osmium and carbon-steel, which is ferro-magnetic, this means if an opponents has the ability to manipulate magnetic fields, they could rip Colossus apart.
Adamantium/Vibranium/Magical/Anti-metal blades: Adamantium can cut through anything except vibranium and adamantium itself. Because Colossus' skin is made of a metal resembling osmium and carbon-steel, it can be cut by vibranium or adamantium. It can also be cut by anti-metal blades as well as magical blades that negate the power of invincibility.
Absolute heat/cold: Due to the fact that Colossus' metal form has a melting point of around 9,000 degrees a character like the Human Torch, who can reach 2 million degrees in his supernova state, could quite easily dispatch of Colossus by melting him down. The same can be said for Iceman, who could freeze Colossus at absolute zero and then shatter his body as if it were glass.
Not long after Piotr joined the X-Men, he witnessed a girl being kidnapped. After saving her, he learned that she was from Russia. Her name was Anya Makarova, a ballerina who had defected to the U.S. After spending some time together, they started to like one another. After she saw Piotr transform into Colossus, she was shocked and no longer trusted Piotr, running away from him.
While celebrating their first Christmas with the X-Men, Piotr met an attractive flight-attendant named Betsy Wilford, with whom he often double-dated with Nightcrawler and Betsy's friend, Amanda Sefton. However, while Kurt and Amanda started a full relationship, Betsy and Piotr were nothing more than close friends.
Nereel and Shakani
While in the Savage Land, Piotr had an encounter with two native women, Nereel and Shakani, who wished to make love with him after Colossus saved them from a thunder lizard. Nereel wished to bring new blood into their tribe. Piotr made love for the first time. The fruit of their union was a son, Peter, born long after Piotr, the elder, left the Savage Land. Colossus is unaware that Peter is his son, despite having met him.
During the first Secret Wars event, all the X-Men but Kitty Pryde were summoned, with other heroes, to another world by the Beyonder. Colossus was injured there, but was healed by an alien girl named Zsaji, whom he fell in love with despite her apparent interest in the Human Torch. After Doctor Doom used the cosmic power he'd stolen from the Beyonder to kill the heroes, Zsaji died exhausting her healing powers to save Colossus. A heartbroken Piotr manages to restore Reed Richards, who subsequently manages to revive their allies. After returning to Earth, Piotr confesses to Kitty and ended their relationship, though eventually they repair their relationship to the point where they are good friends.
When Shadowcat first met the X-Men at age 13, she had a crush on Colossus from the start. Peter and Kitty became close, though at the time, while Kitty made little secret of her attraction to Peter (once kissing him and telling him "Hi, sexy!" in front of everyone in the mansion, making him blush), he was too reserved and shy to follow through. However, during an incident with the alien Brood, in which she actually propositioned him, he indicated definitively that the attraction was mutual, while being mindful of her age.
After Piotr's life was in danger, Kitty promised Caliban of the Morlocks that she would stay with him forever in exchange for his aid in defending the X-Men, although later Caliban released her from that vow. Soon after this, even though Kitty had acted out of love to save him, Piotr started to question the time she was spending with Douglas Ramsey. One problem in their relationship, however, was that Kitty was a devout Jew, and Colossus was raised as an atheist. However, he has claimed to believe in the existence of God. Besides the religious differences, there were several other reasons for Colossus and Kitty not pursuing their mutual attraction for each other further at that time. One was due to their respective ages. Colossus, who was nineteen years old at the time, was a legal adult, whereas Kitty was fourteen, which in the United States and several other countries qualified her as a minor child.
Thus, for him to actually engage in a physically romantic relationship with her would have been inappropriate and illegal. This is why, in X-Men #165, page 19, when Kitty propositioned Colossus, he refused, saying, "However, little one, you are not older." Jim Shooter, the editor-in-chief at the time, disapproved of "the idea of a 19-year-old boy sleeping with an underage girl". Another, albeit related, reason resulted from the X-Men (except for Kitty) being transported by the Beyonder to another world and Colossus meeting and falling in love with a beautiful alien healer named Zsaji. While informing Kitty of this broke her heart, they resumed their friendship later in X-Men #197. Following his return from the dead, Colossus and Kitty resumed a romantic relationship, finally consummating it in Astonishing X-Men #14 (2006).
This reunion is however short lived, as Kitty is forced to sacrifice herself, using her powers to phase a planet-splitting bullet through the Earth becoming fused with it and subsequently lost in space. Colossus still tries asking other superheroes for help in finding Kitty, and bring her back on Earth, but after the events of Messiah Complex, he's depicted as having lost any hope, understanding that starvation or impact with space debris would likely have killed her by now.
When the Morlock Masque altered Callisto's appearance to that of a beautiful woman, she became a supermodel for a short-time in New York during the period Colossus had re-emerged from the Siege Perilous with amnesia. The artist in him became enamored by Callisto's billboard and magazine ads. Eventually the two met when Colossus discovered her being attacked by a gang of street hoodlums wearing X-Men masks near his loft apartment. After rescuing her the two dated for the remainder of his period of amnesia. After breaking up, Colossus returned to the X-Men, and after the death of his sister joined with Magneto. Callisto and Colossus would reunite after Asteroid M was destroyed and they joined forces to defeat Marrow. Before leaving, Callisto and Peter share a final kiss.
Colossus has had other relationships, or potential relationships, develop over the years, such as Meggan, who in fact had developed feelings for him, but eventually ended up marrying her long-time love Captain Britain shortly before Excalibur disbanded; Marrow; and Rogue, with whom he shared some brief kisses after learning Rogue's powers didn't work on him in his metal form. This was something of a retcon since in one early issue Rogue absorbed an injured Colossus' power in order for the Morlock healer to save his life and again after Selene disintegrated his gloves in a battle against Nimrod.
In the Ultimate X-men series, Colossus has a relationship with the speedster known as Northstar. They First meet when the x-men go to the hospital to visit an injured Northstar. Before they departed Northstar complimented colossus. Colossus, instead of blushing, activated his power and turned into steel.