Putting the synopsis again here so others can see the hint
"But destiny is not done with them yet. Granted a second chance, they mend their broken bond and join forces as champions. Together, the immortal and the master unite to protect the innocent from a looming threat."
I don't think that is possible because that would bring trouble, it's been publicly known by cnetz and drama information like this are always carefully handled out by drama team.
No, I don't think it is that simple. I think there is someone who plotted to seperate the two of them and they will reconcile after learning about it. This is also hinted in the synopsis above.
I think there is someone driving them apart and causing them to seperate
I also read others theory that maybe the empyrean is the one driving them apart because they knew that the two joining forces together are very powerful...but yeah it's gonna be a good twist...
"But destiny is not done with them yet. Granted a second chance, they mend their broken bond and join forces as champions. Together, the immortal and the master unite to protect the innocent from a looming threat."
my theory in spoilers below
2. Yes
3. No, it's not the punishment she is mad about. She lost her child.
4. No, the revenge is not for her punishement but something more.
Try understanding HRY pov