Im pretty sure there are two sisters not two sera’s. The story is hinting that Lucy was the original Lucia that ended up somehow leaving the world into “our” world. I think her father who lost his daughter (Lucy), found Lucia by coincidence and adopted her because she looked exactly like Lucy. Now Lucy is back but the author hasn’t explained the full story yet because it’s still getting there.

I don’t get why there’s people saying this is not well written or it’s confusing? This is so good and the pacing is perfect you guys just don’t have any reading comprehension. The story isn’t even crazy complex…