Uncanny X-Men #37-39: Of Course the Big Villain Was A Space Alien All Along

Organizational Note: Starting in issue #38, we have backup stories as well, the first one detailing how Cyclops was recruited by Xavier. Instead of including them with the comics they appear in, I'm going to pop each arc into their own post when one entire backup story arc is completed, as they don't match up with the arcs in the main stories and it would otherwise get confusing.

And now for the big Factor Three finale! Ok, a lot happens here, so let's get started

Our heroes arrive in the Alps, get captured, and then put on trial by the leader of Factor Three, the Mutant Master, with his second in command Changeling, and then the rest of Factor Three, who are all returning characters: Unus, Blob, Mastermind, & Vanisher. The charge? Treason against Mutantkind. Basically each of the four members who have faced them before gives testimony about how "hey they got in our way of being assholes to defend humans" and then Mutant Master declares them guilty. Pretty sure that isn't a fair court.

Anyway Mutant Master declares he is going to start WWIII by attacking a Russian and American base and causing the nukes to start flying so that each blames the other. The X-Men escape, separate into two groups to stop the attacks, Cyclops and Iceman head to the US, Angel, Beast, and Jean head to Russia. They each face some problems, including each group facing two of the Factor Three's members (with Mutant Master and Changeling staying out of it), but ultimate stop the bombs from flying.

They then face off against Mutant Master in his other base, Changeling finds out that Mutant Master really wanted to kill everyone so he frees Xavier and Banshee, the rest of Factor Three turns on Mutant Master as well cause... hey they hate humans but don't want everyone to die. And then Banshee blows apart all the robot attackers, and Mutant masters suit and it turns out he was a weird alien all along who just wanted to annihilate all life on earth to take it over. He commits suicide to avoid... something and then the heroes and villains part ways to fight another day.

X-tra Notes: The writing in these was pretty good. Had some good quips, characters felt like their characters. Why though do they always feel the need to shove in space aliens? Must have just been the sixties. Also, at the end, the heroes all get new costumes so they can look like individuals instead of all wearing the same outfit!