雲の遺跡 (Kumo no Iseki)

Background
Relics of Cloud was first uploaded on November 26, 2011, sung by Hatsune Miku and MEIKO. It did not get much attention, with over 20,000 views (a revised version uploaded a month after of it, reach 200,000.). Yanagi-P then uploaded a Len version of the song on December 29, 2011, which reached over half a million views. That song was also given the title "Legendary LEN Master" for Yanagi-P's fine tuning of Len there.

Len's version was more preferred, with more derivatives or covers with Len's arrangement/version.It's also featured in the EXIT TUNES compilation album Vocalostar.

On July 10, 2012, Yanagi-P uploaded another version entitled "Relics of Cloud (Alternative)" with MEIKO as the main vocals, and also a rearrangement of it (far different than Miku and MEIKO's version, and also different from Len's). The MEIKO version was one of the tracks featured on the MEIKO-only compilation 暁 -AKA-TSUKI-.