What Happened To Everyone Who Joined The Fantastic Four?

After Reed Richards supposedly died, Susan Storm hired Scott Lang as the Baxter Building's head scientist, oblivious that he was Ant Man. When she learned her new employee was a superhero, Sue allowed Scott to take Reed's place in the Fantastic Four.

During his time, the new FF battled a deranged Watcher, an evil Reed Richards, the TVA, the Collector, and an alien called Xlyym. Although Scott's shrinking powers come in handy, it was his ability to adapt to his surroundings and think quick on his feet that made him worthy of the Fantastic Four's legacy.

After investigating her husband's disappearance, Sue discovered Reed was alive and had been trapped in time by a parallel version of his grandson. When Reed returned to the present in Fantastic Four #407, Lang unceremoniously left the team in the following issue.

When he rejoined the team in FF Vol. 2, Scott had the Fantastic Four invade Latveria so he could avenge his daughter, Cassie Lang, after Doctor Doom killed her. Even though Scott is perceived as a small-time superhero (no pun intended), he managed to easily overpower Doom, giving the devilish despot the biggest beating of his life.