The TDs travel through several other universes. One is where Antares never made it back, and has been leading America as president for over a hundred years. He sees the group as a good way to get back to his family in Equestria, and fights Antares in the White House, which destroys parts of it. The group run into others, such as a super Gary Stu TD who is beloved by everybody in Equestria. He had the opportunity to become an alicorn, but he "humbly" declined, but kept the powers. He's beating the others up, but is eventually beaten by The Punchmaster.

"How could you defeat me? I'm so awesome!"

"Nobody questions The Punchmaster."

Finally the group makes it to the heart of the problem, and it is, as many people in the comments guessed, is the Discord possessed TD from Breaking of a Non-Brony. He defeats the group, but Antares helps give Life TD, the TDest of TDs, the ultimate punching power, and he punches the possessed TD in the face, which frees him from the possession, and defeats the evil Discord. Their mission accomplished, the group is each brought back to their own dimension. The story ends with TD and Twilight looking at adopting Comet.

Author's Note

I've retired, https://www.fimfiction.net/blog/1060252/its-time but I still feel like I should tell you how things end.