people are saying this is CDrama version of Scarlet Heart Ryeo. NO it is not.
you will love all the character. ALL THE CHARACTERS. theyre officially BangTan Seonyeondan of Wuxia going on a suicide mission with a badass lady and her badass disciple.
you join them in their journey, got attached, and they all will die at the end. BEAUTIFULLY.

those who said it is open ended; NO it is not.
the child is not NYZ+RRY child, he is a symbol that even after 10 years, those who you love will always be in your memories and their traces is anywhere. you will reminisce them from time to time. you will be reminded of them in everything you do.
he is a reminder to us that a good drama journey will end, and that in future you will meet another great drama having same good details from old one.