I wonder what those who hate each other soul are doing with each other now, like poisoning...

Oh I love that thought (≧∀≦)

Tbh if they switched to the same time points, I'd assume the other emperor is overjoyed to hear the empress has bren dead for years. And then be confused for not having his lovers. And honesyly, probably ruin the country while he's at it - from the translation, it seems to be implied that he wasn't a great ruler.

I don't think he'd be overjoyed. I'd like to see his pov of it tbh.