Chapter 267- Kiss Me Too! (Part 1)
Lein was still in disbelief after hearing Acht's theory, manipulating time was simply too absurd of a power for her to believe it was real. Someone who can manipulate time is basically omnipotent in every sense of the word, a higher being for the lack of a better description.
He can go to the past, change the past and resurrect the dead, he can kill an infinite amount of people even if they gang up on him. He can travel to any place in the world instantly.
All of that was nothing but a drop in the ocean of this ability. So, if it really existed, the whole world could easily crumble down in the hands of that user.
"If he was really that strong, why didn't he just accomplish his goal without the need to create Nightingale."