Niji no Oto

 (虹の音) is the sixth single by Aoi Eir. It, and peaked at #11 on the Oricon single chart.

Single Information
The lead track Niji no Oto was used as the ending theme for the anime special Sword Art Online: Extra Edition.
 * Catalog Number: SECL-1446/7 (Physical Edition)
 * Lyrics: Aoi Eir (Track 1, 3), Furuya Shin (Track 2), Shigenaga Ryosuke (Track 3)
 * Composition: Shigenaga Ryosuke (Track 1, 3), Minamida Kengo (Track 2)
 * Arrangement: Shigenaga Ryosuke (Track 1, 3), Arai Hiroki (Track 1), Kamata Masato (Track 2), Shimokawa Kayo (Track 3)

Limited Physical Edition CD

 * 1) Niji no Oto (虹の音)
 * 2) Yume Sekai (ユメセカイ) (Tomatsu Haruka cover)
 * 3) INNOCENCE (Live at Shibuya Koukaidou)
 * 4) Niji no Oto (TV size ver.)
 * 5) Niji no Oto (Instrumental)

Limited Physical Edition DVD

 * 1) Aoi Eir “Special Live 2013 -Starlight Reunion-” 2013.10.28 at Shibuya Koukaidou
 * 2) Avalon Blue (アヴァロン・ブルー)
 * 3) AURORA
 * 4) Sirius (シリウス)
 * 5) Ei! Ei! Ruuuu!!!!!!