The key we've lost

The key we've lost is Disc 3, Track 1 on the XenobladeX Original Soundtrack. It is split into two parts: the first plays from the start until 3:13, and the second plays from then until the end.

The first part is the battle music for the game's final boss, and plays in the cutscene before the first phase of the boss once Lin agrees to fight, as well as in the cutscene between the two phases. The second part is the battle music for Ganglion, Gularth and Sylooth if the party are on foot when the battle is initiated, as well as the following story battles: The second part also plays during numerous battles in Normal and Affinity Missions, including the following:
 * The Prone Scouts in.
 * The Force Seidr in.
 * Zealot Glennar and the Prone Fighters during Bozé's Way.
 * ST816: Stalio during Bozé's Ignorance.
 * Ga Buidhe, Zo Borri, and Zo Fwar during A Challenger Approaches (only on the first attempt).
 * Blood-king Gelvo Banth, the Prone Boxes, and the Prone Hearthkeepers during The King of Fear.
 * SN333: Jisanne, the Milsaadi Destroyers, and the Milsaadi Corroders during A False Hope.

The first part has vocals written by mpi and sung by mpi and Mika Kobayashi.

Lyrics
(mpi) Let's find the key we've lost Just try to live your life The sun goes down with all my faults So where's your feeling And where is your life?

Let's find the key we've lost Just try to live your life The sun goes down with all my faults So where's your feeling And where is your life?

(Mika Kobayashi) Let's find the key we've lost As all the people cry in vain Just try to live your life The endless sky where I can fly Tell me what you're thinking? Tell me what's your way The end is always here This world locked up in a war

There's a voice that saves your heart and my soul The sun goes down with all my faults So where's your feeling And where is your life? All the clouds, hang dark No one is ever seen

This world locked up in a war

Credits
Lyrics: mpi Music: Hiroyuki Sawano Vocal: Mika Kobayashi Keyboards & Programming: Hiroyuki Sawano Guitars: Hiroshi Iimuro Strings: Koichiro Muroya strings Horn: Otohiko Fujita, Jo Kishigami, Tsutomu Isohata, Atsushi Doyama, Yoshiyuki Uema, Chie Matsushima Additional Voice: mpi