The Decision

The Decision is Disc 4, Track 12 on the Xenoblade2 Original Soundtrack. It plays in the following cutscenes of the main game of Xenoblade Chronicles 2:
 * Jin kills Fan la Norne in Temperantia, and explains his opposition of Indol.
 * Pyra threatens to annihilate herself at Genbu Crown.
 * Enraged after the death of Patroka, Akhos attacks Amalthus.
 * In the year 20XX, Klaus conducts the Experiment, resulting in the worlds of Xenoblade Chronicles 2 and Xenoblade Chronicles (flashback).

It also plays in Xenoblade Chronicles 2: Torna ~ The Golden Country, when Jin joins the fight against Gort in Torigoth, and almost kills him.