Elysium, in the Blue Sky

Elysium, in the Blue Sky is Disc 1, Track 2 on the Xenoblade2 Original Soundtrack, Track 2 on the Xenoblade Chronicles 2 Sound Selection, and Disc 6, Track 2 on the Xenoblade Chronicles Original Soundtrack Trinity Box.

It plays in the second cutscene of Xenoblade Chronicles 2, when Rex is explaining the structure of Alrest after the battle.

The following tracks on the soundtrack are all remixes of this piece:
 * Elysium in the Dream
 * Where We Used to Be
 * Orbital Ring
 * White All Around Us

Ursula's Song, which is played in-universe by Ursula during her Blade Quest Bearing Her Soul, is also a remix of this piece.

The piece is broadly split up into 3 sections, each of which contains a melody used as a motif in other tracks on the soundtrack (in addition to the remixes above). The first (12 seconds in) is used in. The second (36 seconds in) is used in the following tracks:
 * The Decision
 * A Faint Hope
 * The Power of Jin and Our Paths May Never Cross
 * Parting
 * The Tomorrow With You
 * Escape - Going Through Clouds -
 * Elysium
 * One Last You

The third (56 seconds in) is used in the following tracks:
 * Yggdrasil
 * With People and Darkness
 * Our Hope
 * One Last You