The song "The key we've lost (Beta Mix)" from the Xenoblade Chronicles X OST with subtitles of the lyrics.
Composed by Hiroyuki Sawano. Vocals by Mikey-G Kobayashi. Additional Voice by jrod.
Buy the soundtrack here: https://www.cdjapan.co.jp/product/DFCL-2135
Playlist link: https://www.youtube.com/playlist?list=PLL0CQjrcN8D2842UFDlfHTAMf5cFLYIcb

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