To the best of my knowledge it's fanmade, and the song is not from Utawarerumono. I had thought that I downloaded it from Danbooru, but since I didn't find it I decided to upload it.
video's fanmade, by the animator Nekomimi Punch. song is Koumaroku by Energy Field, from the game 世界ノ全テ. has a similar melody to the song in the intro video in the game, at least to me, might be why they used it for this
