It's a cover of one of the first VOCALOID songs posted to Niconico back in the day by the person who is now the most prestiged male solo artist in Japan (Hachi → Yonezu Kenshi)
This is the best cover in your channel and the most important song that you chose to sing. History, magic, loneliness, hope, respect; this video contains many things I don't want to forget. Thank you.
I listened to this song many years ago, it was also popular with American Vocaloid fans... hearing it now is crazy while Miku and "hachi" become popular again. I just turned 30 and feel old and now remember how good this song is again lol. Good work!
I don't know why I feel happy just watching this, maybe because its because I'm also still in school and do music things, or maybe its something else. All I know is that it looks like there have a fun time with music, like me.
So impressed and jelly. So glad as well though that these kids are living out one of my greatest desires from my middle school days. I wish them the best~