The Fall and Rise of the Last Talisman.

The world is known as Itarus, an environment that is polluted with miasma and many different chemicals for humans to not survive. Only mages and other people who are devoted in magic are able to overcome all of these harsh chemicals. Jumu is on the run for detonating six of the plants that are filled with these dangerous chemicals, unable to figure out how to fight all of the enemies from the current timeline, he has no other choice but to use the remaining time travel technology to go back into the past and save the future he once knew from becoming a world that is filled with plague like disasters.