A Russian mutant, Peter Rasputin, is a member of the X-Men and is by far physically the strongest X-Man. Even without his mutant ability to transform his entire body into a form of organic steel, he still stands at a towering 7'5. While in his armored form, he requires no food, no water, or even oxygen to sustain himself and is extremely resistant to injury.
Throughout the series he is portrayed as quiet, shy and innocent as he only reluctantly agrees to use his powers in combat. He feels its his responsibility to use his abilities for the betterment of human and mutant-kind.