Disquiet

Disquiet (originally unofficially referred to as Uneasiness) is Disc 1, Track 17 on the Xenoblade Original Soundtrack and Disc 4, Track 16 on the Xenoblade Definitive Edition Original Soundtrack and the Xenoblade Chronicles Original Soundtrack Trinity Box.

It plays during these cutscenes:
 * Shulk's vision of Reyn being attacked by the in Tephra Cave
 * Shulk, Reyn and Sharla noticing the Mechon in the Ether Mine
 * Alvis watching Shulk and Reyn depart from the distance at the Lakeside in Makna Forest
 * After Shulk's vision of Melia being attacked in the High Entia Tomb at the Centre Gate in Eryth Sea
 * When Junks arrives at the Ventilation Conduit in the Central Factory
 * The party finds Tyrea unconscious outside of Colony 6 during the Melancholy Tyrea