小夜子 (Sayoko)

Background
This song was uploaded onto Niconico Douga on August 8, 2011 and YouTube on February 5, 2015. Since then, it has entered the Hall of Fame on NND, achieving over 500k views since it's upload.

It is featured in Mikito-P's albums Setsuna Plus+ and Boku wa Hatsune Miku to Kiss wo Shita.