Thank you guys for scanlating the manga even with the project being abandoned (which is why the manga has it's own ending because the novels just stopped).
For everyone else who didn't know what happened. The author of the series Suzumu uploaded songs that were not made by him under his name and made money off these songs.
In 2015 he admitted what he did and said that he would stop all his Vocaloid related projects (Meaning Shuuen no Shiori as well).
Words cannot describe how frustrated I am about this situation. I think we can say that we will most likely never know the truth of the story.