Traveling the Heavens: Innately Invincible from the Start

Good news: I transmigrated into the world of The Return of the Condor Heroes and got a System, with innate invincibility as my reward from the start. Bad news: Nobody in this world has reached the innate realm, and apart from people at that level, I can't beat anyone. Ling Feng was an ordinary deliveryman until an unjust twist of fate gave him the chance to board the train of time. The train of time takes you to different worlds. The only way to get off is to survive until the end of the journey. When one story ends, another begins. My story is over. Now it's your turn, young man!