木偶殉歌 (Deku Junka)

Background
The song was first uploaded on January 10th 2010 and is Mayuko's 30th original Vocaloid work. It tells a story of Len, who keeps telling herself that he is a doll. This is an answer song to Mayuko's previous work "Karakuri Hymn" sung by Rin, adding more background to what happened to the two which made them insane as they are.

Unlike Rin's point of view, Len isn't shown as completely insane and focused more on how he could no longer see. As his vision blurs, the memories of the two of them and "that day" (presumably the day where Len lost his eyesight and Rin became somewhat insane).