The Avengers: Doomsday movie is set to break a 26-year rule in the X-Men franchise, as Ian McKellen's Magneto will finally wear the X-Men symbol on his costume. This marks a significant shift in the character's portrayal, as Magneto has largely been an antagonist or a means to an end in the past. The movie's trailers suggest that the Sentinels are hunting the X-Men's universe, and Doctor Doom is behind the chaos. This could explain why Magneto is now joining forces with the X-Men, as his survival and that of the mutantkind may be at stake. The character's change of heart could also be attributed to the events of 'Days of Future Past', where Erik admitted to wasting decades fighting his closest friend, Charles Xavier. With the multiverse in trouble and Doom ready to unleash chaos, Magneto's decision to join the X-Men makes sense, as he stands a better chance of survival with them than alone. The movie's release on December 18th will likely spark excitement among fans, as it marks a new era for the X-Men franchise and a potential turning point for Magneto's character.