No3=NO.EX01

no3=NO.EX01 (called in the JASRAC database) is Disc 1, Track 3 on the XenobladeX Original Soundtrack (making it the third track in 0rCH-SUITE "X"). It is a boss battle track, playing in the following battles, as well as the cutscenes immediately prior:
 * Almandal in Chapter 7.
 * Ryyz and Dagahn in Chapter 8.
 * The Vasara and Deva Caladar in Chapter 9.
 * The Zu Pharg in Chapter 10 (during the 2nd phase of the battle).
 * The Demise Ictus during Then and Now.
 * Ga Buidhe, Zo Borri, and Zo Fwar during A Challenger Approaches (on repeat attempts if the battle is unsuccessful the first time).
 * The first set of Nameless Caladars during Lionhearted.
 * The Marnuck Commander and Marnuck Soldiers during Reporting for Duty (including the prior cutscene when Nagi goes ham on Orton's captors).
 * The Grudge Tersqual during To Serve Nopon.
 * The Twin Qmoeva during Rites of Ruin.
 * The Soghu Caladar during Leaving the Nest.
 * Blood Despair during Rise of the Blood Lobster.
 * The first round of Tectonic Puges during The Duel (Part IV).
 * MO037: Moore during The Duel (Part IV).
 * Ozuchi Caladar during The Gauntlet.

The song was sung by Mika Kobayashi. Official lyrics were never released; the following is an unofficial transcription by Yash K on YouTube.

Lyrics
Wir tragen einen Degen in der Hand Wir tragen einen Gewehr in der Hand Wir glauben, und glauben entschlossen, der Himmel, dass wir sind und wir tragen eine neue Leid

Wir tragen einen Degen in der Hand Wir tragen einen Gewehr in der Hand Wir glauben, und glauben entschlossen, der Himmel, dass wir sind und wir tragen eine neue Leid

Etymology
The no3= at the start of the track indicates that this is the 3rd track on 0rCH-SUITE "X". The significance of 'NO.EX01' is unknown.