One day, the tower started to collapse

In the 22nd century, the last remnants of humanity live in a tower where cities and gates coexist. And I am a time traveler who knows the future in which the tower collapses. My first life ended with my assassination by the mastermind, and I was granted a second chance at the moment of death. To prevent the predetermined apocalypse, I must gather S-class heroes and build the strongest guild... but these guys won't cooperate?