Board Thread:Questions and Answers/@comment-33192803-20170926221323/@comment-76.121.101.29-20170927132508

Hey! I was able to find the song you're looking for (あしたは死ぬことにした). It seems you are right and  it probably was removed due to a copyright stike (or maybe if the youtube uploader was the original producer they decided to delete their channel and stick to ND) but you can listen to the original on nicovideo here!

Hope this helps :)