So Lucy was the real Lucia that finally came back to that world... There's a chance that she got transported to the other world after the northern kingdom fell and distortion of magic or something caused her to fell in the cracks of dimension...And this story is her 2nd life already...means that after returning, bad things happened and Noah died and maybe she also killed herself...And Sena is the one who brought the time back maybe feeling guilt.. and a side effect of that is the creation of the book about their past in the modern world...
So Lucy was the real Lucia that finally came back to that world... There's a chance that she got transported to the other world after the northern kingdom fell and distortion of magic or something caused her to fell in the cracks of dimension...And this story is her 2nd life already...means that after returning, bad things happened and Noah died and maybe she also killed herself...And Sena is the one who brought the time back maybe feeling guilt.. and a side effect of that is the creation of the book about their past in the modern world...