As the world inched irrevocably closer to the precipice of genetic war, Piotr Rasputin stood his ground. The powerhouse of the X-Men, he used his mutant powers to protect those who had come to hate and fear his kind. But the cold, organic steel into which the Russian-born Colossus could transform masked an artistic heart -- a heart of such courage and strength that he sacrificed his life to cure the lethal Legacy Virus!

Real name: Piotr (Peter) Nikolaievitch Rasputin
Occupation: Former adventurer, farmer
Group affiliation: Formerly the X-Men, the Acolytes and Excalibur
Base of operations: Formerly the Xavier Institute for Higher Learning, Westchester County, New York
First appearance: Giant-Size X-Men #1 (1975)

Height: 6'6" (normal), 7'5" (armored)
Weight: 250 lbs. (normal), 500 lbs. (armored)
Eye color: Blue (normal), silver (armored)
Hair color: Black

Powers: Colossus was a mutant with the ability to convert his body tissue into an organic, steel-like substance -- granting him superhuman strength and a high degree of resistance to injury. The composition of this material was unknown, but it appeared to be analogous to osmium and carbon steel.

Weapons: None

History: Piotr Rasputin was born on the Ust-Ordynski Collective near Lake Baikal in Siberia. His mutant abilities emerged during adolescence, but the kind-hearted youngster was content simply to use his incredible strength and durability to aid his fellow farmers. Soon, however, the reality of a world on the brink of genetic war would intrude on the simple life to which he had grown accustomed.

Professor Charles Xavier -- telepathic, telekinetic founder of the masked, mutant X-Men -- contacted Piotr when the sentient island called Krakoa captured his original students. Reluctantly, Piotr agreed to help Xavier's other new recruits. After the battle was won, Piotr remained in the United States with the X-Men. Hated and feared for his strange and frightening powers, Colossus and his teammates stood in opposition to those who would use their genetic gifts to subjugate humanity.

Although half a world away, Piotr's family remained close to his heart and ever present in his thoughts. Despite his best efforts to keep them from danger, his actions often placed them in harm's way -- as when the woman known only as Miss Locke kidnapped many of the X-Men's loved ones to coerce the team into rescuing her employer, the eccentric assassin called Arcade. Among her hostages was Piotr's younger sister, Illyana. The X-Men freed their friends and relatives, and Illyana remained with her brother at Xavier's Westchester mansion. The X-Men proved to be dangerous company. Following one of the team's extra-dimensional adventures, Illyana was held captive for a number of years in the demon-filled realm known as Limbo. During that span, mere moments elapsed on Earth. As a consequence of her captivity, Illyana matured into the adolescent sorceress called Magik. After she reverted to her true age and lost her mystical abilities, Colossus thought it would be safer for her away from the X-Men. But her latent mutation made her a target, even back on the Siberian collective. Illyana's parents were slain by the Soul Skinner, who possessed the ability to strip his victims of their memories. The mad mutant hoped to evolve Illyana genetically, to the point where she would be able to access her powers. With the help of the X-Men, Piotr saved his sister.

When Illyana became the first victim of the mutant plague known as the Legacy Virus, Colossus began to rethink his belief in Xavier's dream of peaceful coexistence between humans and mutants. The philosophical gulf between Piotr and the X-Men grew so wide that Colossus joined the Acolytes, disciples of Magneto -- genetic terrorist, would-be world conqueror and self-anointed Master of Magnetism. Piotr's ideological sojourn was short-lived. Following the destruction of Avalon, the asteroid haven Magneto had created to separate himself and his followers from humanity, Colossus returned to Earth. Piotr set out in search of former teammate Kitty Pryde, the phase-shifting Shadowcat, with whom he shared a special kinship. When Colossus found his dear Katya kissing her then-boyfriend, he nearly beat the other man to death in a fit of jealous rage. Excalibur, England's premier super-team, took responsibility for Colossus as part of his rehabilitation. He came to accept his role and remained until the group's dissolution, whereupon he returned to the X-Men with Kitty and the mutant teleporter known as Nightcrawler.

Following the death of renowned geneticist Moira MacTaggart, the blue-furred X-Man known as the Beast managed to extrapolate on her work to create a cure to the lethal Legacy Virus. However, he was unable to deduce a means of administering the antidote without emulating the manner in which the plague first was discharged: through the death of an infected mutant. The serum would cause the host's powers to flare -- spreading the cure into Earth's atmosphere, but claiming a final victim in the process. Having stood by, powerless, as his sister succumbed to the dreaded disease, Colossus came to a decision that would rock the X-Men. Without revealing his plan, he strode into the Beast's laboratory and injected himself with the formula. Piotr Rasputin, the stalwart X-Man known as Colossus, sacrificed his life to eradicate the Legacy Virus and deliver countless other mutants from death's doorstep.