The song was first uploaded on April 5, 2008 as a "Kagamine Rin original" song. Although Rin's original version invited derivatives, it wasn't until toya made a remake (he had made various remakes to Sleeping Forest) of a Kagamine duet on April 3, 2009 that the song became more notable with over 40,000 views and is toya's most notable work (duet). Overall many other self covers have been made by toya to Sleeping Forest such as Iroha's version, Ryuto's version, Gumi's version, and Len's version.
"Sleeping Forest" tells a story, as the title suggests, tells a forest. Depending on the arrangement / PV / singer, the interpretation may differ from one to another. For example, the duet version of the Kagamines have a PV to interpret the song unlike the other arrangements.