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Shion, are you feeling joy? Happy?

U-DO (pronounced OOH-doo), short for Unus-Mundus Drive Operation (One World Drive Operation), is a wave existence system that is directly connected to the Miltian Conflict and the Zohar.


U-DO dwells in the higher Upper Domain, and can observe mankind in the Lower Domain with its observation terminals, also called its "eyes," Abel and Abel's Ark. It is through this observation that U-DO's power can be accessed, enabling phenomena long thought impossible in the Lower Domain. According to Jr., U-DO is an entity humans could not possibly control.

U-DO is often depicted as pink waves, or a huge cloud of reddish-colored gas with long tendrils.

Connecting to U-DO[]

In ancient times, people used to be together with God. People loved God, revered and even feared God. Out of fear of the undying God, they sought divine power. This was a way for the ancients to resist Him. Eventually, they found a method to become gods themselves.
Dmitri Yuriev
While differing somewhat in the strength of their power, the test subjects assembled in this facility all possess the same ability as Shion. The subjects are capable of communicating with U-DO. They can convey their will to U-DO, but that leads to their own death. The test subjects' wills are unable to stand the stress of direct contact with U-DO, and they eventually fall into a coma and die.
Kevin Winnicot

Aoi Uzuki in a coma.


Xenosaga Episode III - Chapter 4 - Shion's Feelings - U-DO and Shion

Shion communicates with U-DO... over and over... over and over... over and over...

Some humans, such as Shion Uzuki and Aoi Uzuki, share a latent affinity with U-DO, even being able to communicate with it remotely. This characteristic subjects them to psychological stress. Shion begins to exhibit fainting when contacting U-DO.

Direct contact with U-DO strikes humans with a powerful fear, causing a coma, insanity, trauma or death, as with the case of Tethlla Magus. To be specific, humans may see the end of all existence when contacting U-DO, as well as fears of absolute loneliness.

Both Dmitri Yuriev and Voyager contacted U-DO.

Others have the ability to contact U-DO, such as KOS-MOS, the half-human half-Realian Febronia, and the U.R.T.V. units.


Abel's Ark as it appears in Episode II.

U-DO dwells in the higher Upper Domain, observing mankind in the Lower Domain with its observation terminals, also called its "eyes," Abel and Abel's Ark.

When humans perceive U-DO's observation terminal, they perceive U-DO as a brown-haired boy.

In order to assure the continuation of the world and perform Eternal Recurrence, Wilhelm plans on sealing U-DO's observational terminals. Wilhelm calls this covering the eyes of God in order to remove God's influence from the world. Joshua is also able to seal Abel's power.

Time of Xenosaga[]

Dmitri Yuriev and the U.R.T.V.s[]


Demonstration for Helmer

The U.R.T.V.s at the Yuriev Institute.

Dmitri Yuriev, father of the U.R.T.V. units, and others who were studying U-DO, told the government that U-DO was an artificial consciousness or A.I. linked to the U.M.N. that was carrying some kind of dangerous waves. That was a complete lie, told in order to hide the fact that U-DO was something Dmitri Yuriev did not entirely understand.

The U.R.T.V.s are specially designed to combat U-DO; they are U-DO's anti-existence. U.R.T.V.s can produce anti-waves designed to resist U-DO, but these anti-waves will not neutralize each other. The waveform collision between these anti-waves will release enormous amounts of thermal energy, resulting in the destruction of anything near them, including the U.R.T.V.'s.

Miltian Conflict[]


Dive Into MOMO's Subconcious

Albedo comes into contact with U-DO.

A moment before the U.R.T.V.s were to destroy U-DO, U.R.T.V 666 "Rubedo" had a vision of the Old Miltian planet being destroyed in an enormous explosion. Rubedo, fearing for the lives of his companions, broke the psychic bond that would produce the anti-waves. Unfortunately, this left them with no protection against U-DO. U-DO slew or drove mad all of the standard U.R.T.V.s. It then infected U.R.T.V. 667 "Albedo" and drove him mad as well (although he was already a little unstable before that). The only documented surviving U.R.T.V.s were U.R.T.V. 669 "Nigredo" and Rubedo, though Albedo and U.R.T.V. 668 "Citrine" survived as well.

The Abyss as seen in Episode II.

When Albedo made partial contact with U-DO fourteen years prior to Episode I and II (when he was infected by U-DO), it caused a medium-scale space-time anomaly alteration that produced two black holes. The planet of Old Miltia (back then, simply called Miltia) was sucked into those black holes and into a place called the Abyss (possibly just an empty vacuum within the black holes). Since then, U-DO had been obstructed by the two black holes. (In Episode II, fourteen years after Old Miltia's disappearance, Albedo obtained the Y-Data by hacking into MOMO Mizrahi's systems and used it to bring Old Miltia back from the Abyss, sacrificing himself in the process. After this occurred, the two black holes vanished.)

Joachim Mizrahi developed a way to use U-DO as a control system for linking to the Zohar.

Xenosaga Episode I: Der Wille zur Macht[]


Ye Shall Be As Gods

KOS-MOS confronting U-DO at 3:30.

In the Encephalon, Nephilim Verum explains that a time will come where KOS-MOS will encounter the wave existence U-DO. Febronia and Nephilim showed the group a possible future where KOS-MOS fought U-DO and destroyed it along with the universe.

Xenosaga Episode II: Jenseits von Gut und Böse[]

The concept of U-DO is explored more in-depth in Episode II, which elaborates on the U.R.T.V.s. Near the end, Albedo contacts U-DO using the Zohar in the Ω System and creates a space-time anomaly.

Xenosaga Episode III: Also sprach Zarathustra[]

Dmitri Yuriev used Abel to pilot Ω Res Novae. Abel was the only one who could withstand the construct's power without going mad.

On Michtam, Wilhelm seals away Abel's power using Joshua. The 'two Abel', or eyes of God, as Wilhelm calls Abel and Abel's Ark, needed to be sealed away to prevent U-DO's observation of the universe, allowing him to perform the Eternal Recurrence.


  • U-DO has some speaking lines in Episode III; it is voiced by Doug Erholtz in the English version and by Hikaru Midorikawa in the Japanese version. Interestingly, Hikaru Midorikawa also voiced Fei Fong Wong from Xenogears, meaning that the voice of U-DO would also be the voice of Abel in his adult form.



U-DO= Source

Shion communicating with U-DO.


Xenosaga III HD Cutscene 229 - Shion's Self-Doubt - ENGLISH

Shion communicating with U-DO.


Xenosaga III HD Cutscene 312 - Conversation with Abel - ENGLISH

Shion communicating with U-DO.

  • "Shion, a word to define an individual. Are you Shion?"
  • "Shion... what... do... you... seek...?"
  • "I want to know. To know you. To know your world."
  • "I am the will of the universe. You identify me as U-DO. What do you desire from the world?"
  • "Shion, what fills your heart? Is it fear? Sadness... or joy?"
  • "Are you afraid? What are you afraid of? Why are you afraid? Are you afraid of being isolated from the world? Are you afraid of people rejecting you? Are you afraid of your eventual death?"
  • "What does it mean to be alone? Is it more terrifying than death? Why does your face show such an expression?"
  • "This form is what you have defined me as. If you call this form Abel, then I am Abel. I am just one of the ways that U-DO is perceived. U-DO wants to know. About the wills that desire a dissipating world. Everything about you. Everything about this world."
  • "Shion, are you feeling pain right now? Is pain a method to recognize yourself? Why do you all seek pain? You don't know. I don't know, as well. No matter how much you hurt yourselves, no matter how much you hurt others, it won't make you feel better so, why? Shion, why do you exist in this world? What does your heart try to see in the abyss of despair? Where is the real you?"
  • "I want to know. What am I? Who will define me? That's right. I'm alone. Only that song heals me."


Xenosaga Episode II: Jenseits von Gut und Böse[]

Xenosaga Episode III: Also sprach Zarathustra[]