The X-Men's arch-nemesis begins his transition from cardboard cutout villain to tragic figure in this milestone issue. From October 1981, this is "I, Magneto..."
The new X-Men not only faced new enemies, but also was quickly reunited with some old ones, including the Master of Magnetism himself, restored to his physical prime. But we still didn't get much in the way of what really made Magneto tick, aside from a quick scene in Uncanny X-Men #125 of Magneto pining for his late wife as he recovers from a recent encounter with the X-Men. At least, not until this issue. And even then, lots of blanks were still left to be filled, including his name.
Our comic begins with Magneto, using his advanced technology, sending a threat to world leaders from around the globe. He demands that every nation dismantle its nuclear arsenals in order to protect mutantkind from getting caught in the crossfire of a nuclear war, or face utter destruction. As he explains to the currently retired X-Man Cyclops and his human girlfriend, Lee Forrester (captives on his island for the past several issues following a shipwreck and powerless thanks to an inhibitor thingie), the funds spent on such weapons could now go to more worthwhile causes, such as combating hunger, disease, and poverty, ushering a new golden age - with mutants ruling humans and himself ruling mutants. Cyclops counters that there will be resistance, and a Soviet submarine, the Leningrad, proves him correct when it fires a nuke at Magneto's island - an attack he easily repels. He then uses his powers to sink the sub, killing all aboard.