No. 3: X-Men: First Class (2011)
In the first film of the McAvoy-Fassbender regime, they make it apparently clear why they were chosen for the roles of Charles Xavier and Erik Lehnsherr, respectively. Both of these actors do a phenomenal job depicting iconic comic book characters during some of their most vulnerable years. It also shows how Xavier and Lehnsherr first met and what made them friends and enemies, simultaneously. This was also the first X-Men movie to not feature Hugh Jackman as Wolverine, who some may say, carried the franchise for the preceding decade.
Credit: 20th Century Fox
We also get a more in-depth look into Erik Lehnsherr’s past. We saw in previous X-Men movies that he was in a Nazi concentration camp in Poland during World War II. The beginning of this film shows us what fueled Magneto’s contempt towards humans and what helps his powers develop. Most of his power and mentality comes from Sebastian Shaw; Shaw is a doctor in the camps that kills Lehnsherr’s mother and forces Erik to intensify his powers while there. We almost sympathize with Erik because of the circumstances he is operating under.