Board Thread:New on Marvel Fanon/@comment-1359657-20170425052430/@comment-1359657-20170425162709

The reason "Joint Venture" is called that is because Magneto and Professor X co-founded the X-Men together. They're allies here, the oldest and closest of friends.

So the circumstances leading to Onslaught in 616 -- Professor X mind-wiping Magneto in a fit of rage -- never happened in this universe.