Music of Xenosaga Episode III

The music of Xenosaga Episode III consists of 40 officially released music tracks and many other tracks which have never been officially released, including a large number of variations on the officially released ones. All of the music was composed and arranged by Yuki Kajiura. Vocal tracks were sung by Emily Curtis, Eri Itoh, and the Tokyo Philharmonic Chorus.

Musical style
The music of Xenosaga III covers a wide range of musical styles. Two styles are featured most prominently: relatively slow, melodic pieces with prominent strings and piano and less percussion (e.g. a prelude to the tragedy, a new world, and I love you, sincerely), and faster pieces with more electronic instrumentation, often including prominent looped electronic drum beats (e.g. fallout and creeping into). However, many others, such as, do not fit into the above two categories at all.

Looping tracks tend to have relatively limited melody, often roughly 8 to 16 bars' worth, possibly repeated more than once per loop with additional variation. Non-looping tracks (all of which are necessarily cutscene themes), on the other hand, often have much more melodic content, or the melody is more developed and elaborated upon.

Several tracks include vocals, but only one — the ending theme, maybe tomorrow~ending medley — has English vocals. The others are in Kajiurago, a language made up by the composer Yuki Kajiura whose lyrics have no meaning (with one exception — see hepatica (KOS-MOS)).

Variations
Many tracks are variations of other tracks. The extent to which these variations are similar to the original track varies. In some cases, such as when the grief lets you go and, the tracks differ significantly in instrumentation and may differ in structure. (When multiple variations of a track are included on the soundtrack, the variations tend to be of this strongly-differing style). Other variations differ much less strongly, chiefly only via instrumentation; and testament (instrumental) are an example. Yet others, such as Margulis & Pellegri and chaos & Canaan, have only slight differences in instrumental balance distinguishing them.

Use of motifs
Besides those naturally repeated across track variations, there are several melodies that are notably shared across several tracks. Prominent examples are as follows: Several tracks use melodies with origins outside of the game. The most notable external origins of Xenosaga III melodies are (from the Xenosaga II: Jenseits von Gut und Böse ~Movie Scene Soundtrack~) Xenosaga II opening theme/Sweet Song (Xenosaga II ending theme),, and fatal fight (Jin & Margulis), and (from the music of A Missing Year) my long forgotten cloistered sleep (unreleased work of Xenosaga).
 * The melody of the title screen, arguably the main theme of the game as a whole. It plays in title screen (piano ver.), I love you, sincerely, maybe tomorrow~ending medley, I love you, sincerely (piano ver.), maybe tomorrow (violin ver.), maybe tomorrow (piano ver.), chaos & Nephilim, and to the last place.
 * The melody of mother, I miss you, which primarily plays in situations involving Kevin. It is used in a prelude to the tragedy and promised pain (and the medley section of maybe tomorrow~ending medley).
 * The melody at the start of maiden of the apocalypse also features in battle vs. Yuriev,, and the medley section of maybe tomorrow~ending medley.

Functionality in-game
About 75 tracks (including variations) function as cutscene themes. 13 tracks play in battle, and 23 are area themes, playing in the overworld. There is some minor overlap; several cutscenes use as their music the area theme in which they are set. More commonly, two different variations of the same track may play in different circumstances (for example, compare survive — a battle theme — with, a cutscene and area theme). Sometimes, as is the case with and promised pain, a battle which uses music with vocals will be preceded by a cutscene which uses a non-vocal version of the battle theme. There are also several tracks that play only in menus, including HaKox.

Unlike in Xenosaga Episode I and Xenosaga Episode II, there is no victory theme and no 'game over' theme; the battle music continues into the results screens, and no music plays on the game over screen.

Not all of the music featured on the soundtrack was included in-game: on our ways,, and the medley of maybe tomorrow~ending medley do not play in-game. There are also several tracks which have minor structure elements on the soundtrack which do not feature in their in-game context (mainly looping tracks), such as the start of the battle of your soul and the end of survive. Finally, many tracks and variations of other tracks appear in the game's files but never play under normal circumstances, such as maybe tomorrow (piano ver.).

Track titles
Only officially released tracks (those on Xenosaga III: Also Sprach Zarathustra Original Sound Best Tracks) have official titles. These titles, in accordance with Yuki Kajiura's naming schemes, are typically in all lowercase (proper nouns are the main exception). Where a track is a variation of another track (and both tracks have proper names), the variation will typically have the same name as the original, but with an appended '#2' or '#3', such as. (Note the lack of a space before the '#'; Xenosaga III titles differ from Xenosaga II titles in this manner.)

Tracks which were not included on the soundtrack have no official titles. Some have widely-used unofficial titles; others do not. The distinction almost exclusively comes down to the manner in which the music is stored in-game.

Area themes, battle themes, and menu themes are always stored independently as their own file in the game's code, as the manner in which their audio will be overlaid with dialogue and sound effects is not pre-determined. The same is true for any cutscene music which plays in a cutscene with manually advanceable dialogue, as different players could advance the dialogue at different rates but the music always plays at the same rate. As these tracks are stored as their own files, they have been extracted and made into playlists since the game's release, and the resulting discussion has produced unofficial titles. (These tend to broadly align with Kajiura's naming schemes in that they use all-lowercase except for proper nouns.)

However, there are some cutscene themes which never play in cutscenes with manually advanceable dialogue, and so the manner in which their audio is overlaid with dialogue and sound effects is pre-determined. Therefore, these tracks were not stored as their own audio file in-game; rather, they are simply a part of the cutscene audio file. This makes clean extraction of the music impossible (with current technology), and so they have not been (and cannot be) uploaded independently. As a result, discussion surrounding these tracks is limited and as of 2022 they have no widely-used unofficial titles. A list of tracks to which this applies is as follows:
 * title screen (piano ver.)
 * revolution
 * awakening of the saint
 * maiden of the apocalypse
 * Voyager (ambience ver.)
 * maybe tomorrow (violin ver.)
 * a sibling's farewell
 * the land of origin
 * maybe tomorrow (violin ver.)
 * a sibling's farewell
 * the land of origin
 * the land of origin

Xenosaga III: Also Sprach Zarathustra Original Sound Best Tracks
Xenosaga III: Also Sprach Zarathustra Original Sound Best Tracks is the only official release of the music of Xenosaga Episode III, released on 2 CDs under Victor Entertainment on 12 July, 2006. It contains 38 tracks used in Xenosaga Episode III plus two which went unused.

The organisation of the tracks is unorthodox. Aside from the first two tracks (which play at/near the start of the game) and last three tracks (which play at the end of the game), there seems to be little to no correlation between how early a track plays in-game and how early it plays in the soundtrack. For example, the final boss theme and last area theme both play in disc 1 of the soundtrack. Moreover, there are oddities such as coming before hepatica (KOS-MOS). It is possible that the tracks were simply placed in an order which Kajiura believed to constitute a good listening experience.

Other
The only piece of Xenosaga III music not on the Original Sound Best Tracks album which has nevertheless had an official release is U-DO~Febronia, released as part of the Xenosaga II: Jenseits von Gut und Böse ~Movie Scene Soundtrack~.

Unreleased music
A very large amount of music composed for Xenosaga Episode III was never officially released. The following is a list of such tracks, organised by function and the order in which the tracks appear in-game. (Unused tracks listed below were all kept within the game's files but do not play during normal gameplay.)

Menu themes

 * title screen
 * HaKox theme 1
 * HaKox theme 3

Area themes

 * beach
 * I love you, sincerely (piano ver.)
 * CAT Facility
 * Acute Neurosis Treatment Facility - under attack
 * Old Miltia Forest
 * rescue of Virgil
 * Acute Neurosis Treatment Facility
 * Labyrinthos - search for Shion
 * Abel's Ark
 * rescue of Virgil
 * Acute Neurosis Treatment Facility
 * Labyrinthos - search for Shion
 * Abel's Ark
 * Abel's Ark
 * Abel's Ark
 * Abel's Ark

Cutscene themes

 * the body of the saint
 * S-Line Division infiltration
 * discovered!
 * a new world (piano ver.)
 * chaos & Canaan
 * floating landmass appears
 * title screen (piano ver.)
 * Yuriev & Sellers
 * omega (instrumental)
 * Shion's reunion
 * chaos & Nephilim
 * Juli's briefing
 * revolution
 * testament (instrumental)
 * T-elos's challenge
 * awakening of the saint
 * Margulis & Pellegri
 * sneaking around in Miltia
 * Suou & Shion
 * Jin
 * Song of Nephilim (Xenosaga III ver.)
 * Virgil's lament
 * T-elos's final appearance
 * maiden of the apocalypse
 * the harsh truth (piano ver.)
 * Joachim's decision
 * destruction of the star system (short ver.)
 * start of CAT infiltration
 * promised pain (instrumental) ~ Zarathustra out of control
 * destruction of the star system
 * Richard & Hermann's appearance
 * Voyager (ambience ver.)
 * maybe tomorrow (violin ver.)
 * Wilhelm
 * Nephilim & Abel
 * a sibling's farewell
 * the land of origin
 * Voyager (ambience ver.)
 * maybe tomorrow (violin ver.)
 * Wilhelm
 * Nephilim & Abel
 * a sibling's farewell
 * the land of origin
 * a sibling's farewell
 * the land of origin

Battle themes

 * minor boss battle
 * battle vs. Yuriev
 * battle vs. Erde Kaiser Sigma
 * battle vs. Erde Kaiser Sigma

Unused tracks

 * a new world (remix)
 * Joachim
 * omega
 * maybe tomorrow (piano ver.)
 * HaKox theme 2
 * omega
 * maybe tomorrow (piano ver.)
 * HaKox theme 2

In other media

 * the battle of your soul was remixed for Project X Zone. Similarly, she's coming back was remixed for Project X Zone 2.
 * godsibb was performed at YUKI KAJIURA LIVE 2008.07.31, a live performance of Yuki Kajiura's works on 31 July 2008. The performance was included as track 15 on the associated DVD.
 * maybe tomorrow~ending medley was redone as maybe tomorrow for FICTION II, an album of a selection of Kajiura's works released on the 30th of March, 2011. This version had slightly different instrumental balance, and the medley was replaced with an extension of the section preceding it (the part after the medley was kept intact).
 * hepatica (KOS-MOS), godsibb, and (the FICTION II version of) maybe tomorrow~ending medley were performed at FictionJunction 2010-2013 The BEST of Yuki Kajiura LIVE 2, a live performance of Kajiura's works on the 3rd of June 2015. They were included as disc 1 track 5, disc 1 track 6, and disc 2 track 9 respectively on the associated album. (In this release, hepatica (KOS-MOS) was called 'hepatica' and maybe tomorrow~ending medley was called 'maybe tomorrow'.)
 * hepatica (KOS-MOS) was performed at Yuki Kajiura LIVE vol.#15 ~Soundtrack Special at the Amphitheater~, a live performance of Kajiura's works on 10 June, 2020. The performance was included as disc 2 track 9 on the associated album as 'hepatica (XenosagaIIIより)'.
 * godsibb was performed at Yuki Kajiura LIVE Extra Edition-STUDIO Delivery LIVE vol.#1 Reprise, a live (virtual) performance of Kajiura's works on 18th September, 2020.