背徳硝子ウォール (Haitoku Glass Wall)

Background
"The Immoral Glass Wall" is SASA's seventh work; and his first to feature a Rin and Len duet. The song was first uploaded on October 10th 2012 and is among SASA's known works with the others being "Sonzai no Answer", and "Boundary Door" sung by Rin. SASA's comment on the video questioned why the twins wanted to be together.

The song tells a story of forbidden love between Len and Rin with the "glass wall" as the border of their relationship. All in all their feelings can not reach each other, and they can only dream.