The created world of Xenogears and Xenosaga, nicknamed the 'Xenoverse', is composed of 3 major parts within an infinite flow of history. The time scale involved is more or less that which encompass the entire history of our universe. This section will closely examine the 3 main parts of the story and its history (the world's background) in order to guess at its beginnings, endings, and meanings.

Due to the large amount of information about this world, it is possible to determine the cause and effect that takes place from past to present, and by listening to the voice of its creator, the facts that were not revealed in the games will be examined here, and hopefully the world in its entirety will be understood.

Part 1: The epic story arc of human Fear

Also known as: Xenogears EPISODE I Xenosaga Episode I-II (original Xenosaga plan) Xenosaga Trilogy/Series (current state), 'Cosmo War', Shion's arc, etc.

Part 2: The epic story arc of human Grief

Also known as: Xenogears EPISODE V, or II-V (or Xenogears "the game") Xenosaga Episode III-IV (original Xenosaga plan) 'The World of Fei', Fei's arc, Lost Jerusalem arc, etc.

Part 3: The epic story arc of human Anger

Also known as: Xenogears EPISODE VI Xenosaga Episode V-VI (original Xenosaga plan) 'Terminal point of the universe', the final chapter, final arc, etc.