Night is kind of not redeemable to me. At least if the drama keeps going by the book. I mean the only actually selfless nice thing he does is give XF the paintings JM made of him. I think he found some sort of inner peace by the epilogue. I have been seeing a lot of comments on how Night has the right personality to be an Emperor like scheming, backstabbing, etc. So that he was destined to be Emperor while XF was more of the give up everything for love type of guy. In the end, Night ends up being a lot like the current Emperor in what he did in order to reach the throne.
I wouldn't mind a side story with Night and how he redeems himself in some sort of way. While I do think his actions towards XF and JM are 100% wrong. I also think he realized a bit that he was wrong after JM jumped in front of XF and that is why he let them be at the end. So it would be interesting for them to show him doing something to redeem himself. But if I were XF or JM, I would still never want to see him again.
lol at how they filmed this