5. Mastermind: illusion specialist
Mastermind brings a direct connection to the original Brotherhood of Evil Mutants, but Factor Three gives him a place in a different organization. He serves under Mutant Master and alongside other enemies who already have reasons to resent the X-Men.
At the trial in X-Men #37, he is one of the four familiar villains used to justify the charges. The story also acknowledges his return after the Stranger’s earlier attack, explaining that the transformation into a solid form did not last.
His most useful field scene arrives in #39 at the American missile base. Cyclops and Iceman have reached the air-filtration equipment to prevent Factor Three’s gas attack. Mastermind arrives with the opposition, using illusions to get past the military personnel outside.
Once the fighting starts, his power interferes with Iceman directly. Illusory restraints disrupt Bobby’s attempts to aim and use his abilities. That gives Unus room to press the physical attack against Cyclops.
Mastermind does not need to hit harder than the X-Men. He can make their immediate understanding of the fight unreliable while someone else closes the distance.
The scene also keeps his position in perspective. He is a capable participant in the missile-base operation, not the author of Factor Three’s grand strategy. His contribution is deception at the level of the encounter: getting into position and making an opponent hesitate.
5. Mastermind: illusion specialist
· Comics / Marvel / X-Men