time travel methods in fiction

Alister Wright was one day unexpectedly transmigrated into a world of modern fantasy. A world where people could use superpowers, like in those novels he used to read. But it wasn't a dream come true as one might expect it to be, it was a nightmare. In this new world, dimensional gates descended, and monsters waged war against the human race, To make matters worse, in such a dangerous world, Alister was transmigrated into the body of a nobody with no talents and supernatural powers. Not just a trash, but the trashiest of them all known to the world after breaking the world record of awakening a 0-star talent! Receiving the scorn and mockery of the world, it was a despairing situation for him. Nonetheless, he persevered and didn't give up. But when all hope was lost and there was no salvation in sight, A miracle happened and Alister finally awakened his golden finger. [The World Travel Simulator is online] "Finally!" The World Travel Simulator System, a cheat system that could simulate another real world, creating a temporary replica of everything like a mirror world where Alister could travel to and explore freely. It was like another life, and to top it all off, the greater his achievements in that world, the greater he would be scored by the simulator system. Kill some mobs, it was F- grade. But... Uncovering the mastermind or defeating the strongest, it was a guaranteed S-grade! Depending on his grade, he could inherit the power, talent, knowledge, and experience he had in the simulation. [If the host can get S-grade in the simulation world, it will become permanent and the host can transmigrate into that world by performing a full-dive realistic simulation but with the risk of true death.] "But what if I get another S-grade score in that world during the realistic simulation?" [After obtaining another S-grade simulation score, the host can obtain the ownership of that world and become a World God!] "WTF? ARE YOU SERIOUS?... This... This is... AWESOME!!!!" "Hahahaha" Alister laughed manically. "So what if you're the strongest? What if you can kill me? Heh! I'll keep on simulating. I'll keep on returning back until I defeat you!" "I will fight with you countless times in that simulation, know every future, and come back to kill you and give you the worst possible death... Mark my words... GOD!" A transmigrator, system user, and even a regressor. With those identities of his, Alister vowed to become the strongest! *** Join the discord server: https://discord.gg/BX9ZDY6mdT