The song is called Kasou Kyoku, also known as Cremation Song or Cremation Melody.
I just don't know, but this song really just caught me in the moment, and I began to draw this picture.
Faucherevere! Italy and Italy are singing the song together, however, Italy is just a porcelain puppet and Faucherevere! Italy began to take over his body (if you look at Italy's crying face and his normal hand, it's cracking).
Kasou Kyoku --> youtu.be/xrue8UalhBM
Eng. Lyrics --> www.quotev.com/story/1349431/V…