In some of my comics time travel has presented itself as devices of several plots. One story line involves the future changing drastically and the descendant of the present day hero goes back in the wrong date and warns the hero. As a result, future forces from the same time reality have also come back to prevent the rise of the resistance. A battle throughout time occurs. Another involves the same character using the time device given in previous story line to personally see the history of an era for a report. But his presence creates an alternate reality he must prevent. Because it is superhero comics, I have some characters who can manipulate the flow of time and with enough energy, even travel time, though very rarely. In the later part of the series in question, I decided in order to incite a dark transformation in the main character, his girlfriend needed to be killed off. Because of this, his superhuman energized soul is corrupted by anger, hate, and revenge. Like Batman, he is now on the hunt for past and present enemies as well as those responsible not looking to just defeat them, but to kill them, causing him to be a monster. With this story line, time travel is indeed involved, but I don't want to use it as the Dues Ex Machina by going back and preventing the girl's death. I want this story line to be the end of all time travel so I won't have to use it as a cop out. There are a couple things here. One is time travel is accomplished with highly advanced technology that was invented far into the future. Two is one of ten gems of the universe that gives the user control of time. I'm probably going to make it where the time travel tech is all destroyed and the gem is lost after the main character defeats his demons, so he won't be able to cop out. I made it to where it lines up with the continuity of previous stories and involve clones, so I don't need to cop out, I just need to know how to kill of time travel permanently as a plot device or Dues Ex Machina. Also, thank you for having the patience to read all of this. Lol.
It might be too late in the development of the series to add this, but you can always make the actual act of time-traveling take a physical toll on the individual, like the human body is only capable of traveling so much through time, that too much traveling through time causes seizures or something like that, potentially killing themselves.You can also have someone go back in time and prevent time travel from being invented. Not sure if that will help if your character needs to get back to the present but hey, he's a superhero, he can use that gem to get back.
How are you addressing paradoxes in this story? And why if he has the power to time travel would he go on a murderous rampage for revenge instead of actually saving his beloved girlfriend? For the destruction of time travel what kind of time travel are we talking about here? Are you using a completely linear timeline where the characters are simply jumping backwards and forwards at leisure and without really changing anything like Back to the Future or are you using a multi-verse type timeline where all the different actions and decisions branch off into a new timeline like in Bioshock Infinite? If it's a stable linear timeline you could go either a long way back or a long way forwards and either hide or destroy it in Lord of the Rings style with a volcano throw or something. Though that kind of depends on whether that would create a paradox or not and the actual requirements for the device or tech being destroyed.
