Board Thread:Manga/@comment-27321453-20190908104148/@comment-1327106-20190919033154

SunWarriorAsahi wrote: He didn't change the past, but he made the past happen, that makes NO sense. DX

It works with a fixed timeline/stable time loop. You might not like it, but it's one of the established types of time travel in fiction. The first Terminator movie makes use of it (Kyle Reese goes back in time and becomes John Conner's father, without which John Conner could never have sent him back in time in the first place). Maybe you didn't like that movie either, but the fact remains that this is not something new that Isayama made up. In fact, this is the only type of time travel that Einstein thought might be realistically possible because it means paradoxes cannot happen, because you can't change the past (or the future if you know it).

Zeke's words support that without Eren's interference the past wouldn't have happened. He sees Grisha doesn't want to kill the Reiss family and that Grisha's current course of action would deviate from history, which he considers impossible. Then Eren gives "the talk" to Grisha, and Grisha follows through, making history occur exactly as we know it.

If Eren did not interfere, a different timeline would have happened, and it would be radically different, since the Reiss family would have survived and Frieda would have kept the Founding Titan. That didn't happen. By interfering, Eren preserved the existing timeline, thus he made the past happen the way it did.