Disclaimer: I don't own the story, Tabata does.
They say there are multiple parallel worlds. And in every world, there are always subtle changes between the next one. Because of those subtle changes, the parallel world may either be identical or different.
In this world, a lot of subtle changes happened, making it far from indentical to the real one. For example, the main character of this story has magic while in the real world, he never has. He was loud but calm in this parallel world.
Another of this is a new character. He lingers in their past but not in the present. He guides the main character and teaches him during his sleep.
But in spite of this changes, many things stayed the same. Like for example: Yuno's personality, Father and Sister's personality (probably all of them except Asta.)
From the start, everything was normal. From their personalities, faces, playfulness. But as soon as they have grown, everything changes. Physically and mentally.
This is a story of the two child who were left in the church at the same day and the same time. A coincidence? Maybe not.
Read at your own risk*
Warning: A lot OP characters, mainly the MC. If you don't want this kind of fanfic, please don't criticize and just pass this one.
(Sorry for the typo and wrong grammar. As well as some wrong spelling. English is not my first languange. I hope you umderstand.)