
The very fact Sehyun gave a dedicated letter to Tracy at the end! So many many, even major manga/anime don't give credit to those that died, much less a flashback at the end of the series or manga. Yet Sehyun did it for a girl he never met! All he knows is it that she's the reason Boris saved his life, beautiful story!!
Honestly, nowadays anime/manga have such cliffhanger, bad or out of nowhere endings, that finding one as good as this is hard to come by. Yeah not all the characters make it but it still gives you a warm wholesome end.