A Life Sent On

A Life Sent On is Disc 2, Track 12 on the Xenoblade Chronicles 3 Original Soundtrack and Disc 13, Track 12 on the Xenoblade Chronicles Original Soundtrack Trinity Box. It was used in promotional material for the game: Noah plays a section of the piece's opening at the start of the game's reveal trailer, and 1:11 in the track plays towards the end of the trailer. The full track is playable on Xenoblade 3's official Japanese website by pressing a button labelled 'BGM', and was also released in a tweet by XenobladeJP on Twitter.

It plays in the following cutscenes. In all such cases, the flute lines are played in-universe (the orchestral accompaniment, which plays in some instances but not others, presumably does not play in-universe). Whether both flute lines play during all sections of the piece is dependent upon cutscene.
 * Noah and Mio send off Guernica Vandham in.
 * Noah and Mio send off Consul K in.
 * Noah and Mio send off the 'soldiers' they 'killed' in the fight against Lambda Ferronis, while the rest of the party reflects upon their reasons for doing so, in.
 * Noah and Mio send off Ethel and Cammuravi in.
 * Young Noah hears flutes playing this theme after time resumes in the post-credits cutscene.

Noah and Mio play excerpts of the piece's flute lines when Off-seeing. In gameplay this momentarily replaces the area music; which flute line is played corresponds to which flute is used in-universe (the lower line is played by Noah's black flute while the higher line is played by Mio's white flute). When off-seeing multiple husks, the characters play both lines together.

The piece's high flute line is also called Off-Seer - Mio, and the low flute line is called Off-Seer - Noah. Both lines are used (independently, although often together) as motifs in a very large number of other tracks, and as such A Life Sent On shares portions of its melody with much of the rest of the soundtrack. For full lists of such tracks, see the pages for Off-Seer - Noah and Off-Seer - Mio.

Trivia

 * A Life Sent On was the first piece of music composed for Xenoblade Chronicles 3.
 * The flutes used for the recording of A Life Sent On were instruments the developers had custom-made with the design of those of Noah and Mio in-game.