Alright, for anyone confused about the time travel, it's really not that difficult. To summarize, there's two timelines, the original and the current.
In the original the country of Altein created a form of magic that led to them taking over the world. Part of that act was crushing the elves, which led to Elria in that world creating her own style of magic and damn near destroying the world with it, to the point of creating the Calamity that's still causing problems. Her father used magic to go back to before Altein made magic and tweaked past Reid who had made the original Altein's magic to be buff instead. This started our story's timeline.
In the story's timeline, Altein still went to war cause apparently they just suck for that, but in this one the elves weren't stomped nearly as hard, leading to Elria making magic that leveled the playing field well enough for it to be a long war. Fast forward till she dies, Reid goes on his rampage to die by her side, they both reincarnate eventually. While they're dead, Elria's dad wipes Altein cause they don't have their hero and probably kind of deserve it, to be honest.
Enter the current story, where Altein from the previous timeline, which is still a thing that exists, is probably using the traces of Elria's dad's time travel to locate this fresh new unravaged world and are trying to shift themselves into this new world because they don't want to die off with their own world. Still being assholes with their methods, even if the goal is understandable.
