So, here's where I expand on this original sequence;
1.
URTV enter the Nephilim to eliminate U-DO 2.
Rubedo closes his mind out of fear of U-DO's fury/going out of controlODM:
Furthermore, Jr. closed his heart out of fear of U-DO's running out of control and cut the mental link with the other U.R.T.V.s. Because of this the channel that connected the U.R.T.V.s together was opened and left defenseless and due
to that they became able to be tainted by U-DO.
The URTVs, who were produced for the sake of searching for the possibility of eliminating U-Do, will eliminate their own personal reason for existence when the time comes that U-Do is eliminated.
3.
Albedo is infected/URTV go insane due to U-DO ODM:
When the unleashing of U-Do occurred on Miltia 14 years ago, Albedo received a surge of U-Do, which caused a severe change in his emotional state.
In-game dialogue:
Jr.: (furious) Shut up! I don't need some freak contaminated by U-DO to
tell me…
Shion: Jr.…?!
Albedo: Contaminated? Not quite. More like…evolved. I experienced but a fragment of my true power that day. The waves that inundated my body are now a part of me! I've reached a higher stage of existence compared to you incomplete mortals.
4.
Some time after Albedo's infection, the URTV are separated. Encephalon Flashbacks - Gaginun is searching for Rubedo in Miltia City
5.
Gaignun eliminates the rogue URTV (though apparently via a rifle, rather than any special ability) while looking for Rubedo. Encephalon Flashbacks - URTV are shown bearing rifles;
Gaignun shoots the rogues down
6.
Gaignun returns to Nephilim chamber, possibly to look for Albedo or Rubedo7.
Albedo, now empowered by U-DO waves, attacks from Gaignun from behind Encephalon Flashbacks - Albedo strikes Gaignun from behind
8. Rubedo enters Nephilim, finds Gaignun wounded, Albedo emerges and claims to be "perfect chain" (as depicted in Jr.'s dream)
Jr.'s dream - Jr. finds a wounded Gaignun in the Nephilim, Albedo's waves emanate from behind
Encephalon Flashbacks - Albedo's mirror-mirror speech
9.
Albedo and Rubedo duel, with Rubedo pushing his power to its limitsNever explicitly shown, but strongly implied.
Flashbacks show:-Albedo is seen to rise from behind Jr. with Gaignun wounded in Nephilim
-Jr. is shown to be carrying wounded Gaignun outside in his dream/flashback outside the Nephilim
Evidently, a confrontation between Jr. and Albedo must've taken place in-between.
In-game dialogue corroborates this:As Albedo and Jr. duel in present day:
Ah, Rubedo. You're getting closer to your old self. But you're still not quite there yet. You were much stronger than this back then, weren't you?
Indicates the two have dueled before.
Albedo: Please spare me from any trite lines like, "You're still alive?"
Evinces Jr. believed Albedo to be dead.
10. Albedo loses duel and, critically wounded, falls to bottom of Nephilim-Can be inferred from the DS meeting with Kirschwasser, that this was to take place in OE1C.
11.
Rubedo, having overextended himself, suppresses his powers to survive and stops his aging process. Leaked Notes: During the final anti-U-DO operations (14 years before the story begins), Jr. had to face off against Albedo… Dealing with him required Jr. to use all of his abilities to their utmost limits, consuming the majority of his life expectancy in the process. As a result, he has suspended the growth of his body indefinitely.
ODM:
#666, Jr, is performing the suppression of physical growth and can even be said to suspend time with his own will. Also, Jr is considered to be playing the
role of central connecter that psychically ties together his other fellow
URTVs. The reasoning for this is that, on Miltia 14 years ago, because Jr became terrified by U-Do's fury and rejected the mental link, which caused the other URTVs to become completely chaotic.
In-game dialogue:
Mary: It's a shame… Little Master doesn't have any choice in the matter but to stay that size…
-Suggestion that Jr. has no choice, but to stay ageless. Fits with the " life expectancy" explanation.
12.
Rubedo carries wounded Gaignun out of Nephilim; they leave Miltia by means unknown, though Helmer rescues them:
See point 9, in addition:
ODM:
The person who was commanding the Galaxy Federation Army is the person who has currently seized the real power in the Second Miltian government, Helmer. He rescued Jr. and Gaignun who had been seriously injured in the Conflict and
after that he was also the person who entrusted the Kukai Foundation to Jr. and Gaignun.
13.
Albedo presumably ends up with U-TIC/meets the Kirchwasser-See point 10