Ok, so we all know that Deep Dive was the Roxas/Riku fight where Roxas was thrashed and sent to Data Twilight Town for rehabilation.
Through Days, we got a reason why Riku did not cut down on Roxas as he passed, which was because of
And the reason why Roxas did not cut down on Riku, which was because of Roxas taking pity on the poor enemy who would not cut down on him anyway.
Then we go about to the 2nd generation of Deep Dive, the Sora/Xemnas version. It was an 'illusion' Memory's Skyscraper that Xemnas threw Sora into, for reasons that we know not, since we obviously realise that neither Sora or Xemnas were actually damaged by the end of that fight, just as how in Roxas/Sora Sora was not injured either (particularly apparent in FM+ real battle). So it's basically a non-existant fight.
The reason for the Roxas/Sora battle was just, well, Roxas wanting to find out why Sora is the wielder and all. But what is the purpose of Xemnas putting Sora into that illusion Memory's Skyscraper to fight there? That is what this thread will explore: The significance of Deep Dive.
Since there was no real conclusion to such a fight, aka neither Sora nor Xemnas was taken out of the game, the fight should have bore no significance to real flesh/blood combat. Neither did Xemnas know about Riku/Roxas battle. Ok, fine, he may have knew, since it happened in his domain, but why would he want to stage it once more, for example, why didn't he just give them a fight, at, say, Hall of Empty Melodies? Also, why did he take the position of 'Riku' in Deep Dive by being the one at the top of Memory's Skyscraper?
Possible hypotheses include:
1. Reminding Sora that he is weaker than Xemnas by taking the place of the 'winner' of that combat. However, Sora had received no memory from the chain by Roxas, apparently not remembering the Organization crap, so it seems unlikely, and would achieve nothing anyway.
2. Possibly trying to pull out Roxas' personality/conscience from Sora, by staging an event he would remember. It is possible since
And he wanted Roxas to return to the Organization of free will in such a way. However, unlikely because Sora was the leading man in that mix and there would be no way until Xemnas divides Roxas and Sora. Which would not actually work unless the battle occured within Sora's heart. Which may have happened, but is unlikely unless Xemnas had a proper connection to Sora like Roxas.
This hypothesis thus gives us a possibility that, in some way, Xemnas is related to Sora to awaken the battle within his heart, in an attempt to try to draw Roxas out for a reason. Unfortunately, we do not know whether this is possible.
3. Possible past event between Xemnas and someone else that was coincidentally repeated by Riku/Roxas, to the extent that Riku and Xemnas bear a resemblance and connection in a way that they are trying to capture the other faction, or even down to personality/role of relation between the people. In this way, a Deja Vu situation is created where Xemnas wishes to 'capture' the opposing party, perhaps forcing an awakening with the awakened memories. Unlikely for Roxas, but maybe someone else in Sora.
Obviously, in this hypothesis the obvious contender will be Ven, which Xemnas hints to as knowing in Days, with a relation to Xion as well, and seeing that Roxas and Xion both are in Sora and they share common points with Ven, it may be possible that Xemnas is trying to reawaken Ven through the memories, in this hypothesis.
By going through with this hypothesis, it can be deduced that Ven and the person Xemnas was, Xehanort, may have once gone into conflict in a similar manner to Deep Dive, perhaps not at Memory's Skyscraper (since TWTNW was not even built yet) but at someplace else that can provide a similar scenario, to capture or defeat Ven to achieve a certain purpose.
Then we should also consider the environment that the battle was conducted in. Why was the whole place like a blend of confused thoughts? The whole place was not even solid looking by far apart from the small portion where they were fighting in. This gives the sort of impression that the battle occured in the mind. Unfortunately, mind is not a logical place to fight in Kingdom Hearts where everything is Heart, Body and Soul. In such a situation, I create the hypothesis that they are, in fact, fighting in a place of Memory, Sora's Memory, probably drawn from Roxas. Thus, it lacks the clarity such as in Sora's battle with Roxas. In such a way, Xemnas is able to access the Memories of Sora (seeing as Sora was not actually moving or anything from his body during the actual fight). This can be reasoned with the fact that Xemnas had once encountered Sora and his memories in the optional battle of KH: FM, and thus he can do so.
However, that does not mean that he would be able to manipulate the memories to create the scene of the battle from a range. Thus, there has to be a connection of Sora's Memory and Xemnas. Once more, it may be possible to link Ven into this situation, because Ven may have had a close relation with Xehanort, and seems to have a relation with Roxas too, thus he may have been the link between the memories of Deep Dive by Roxas and Xemnas.
Next, we consider why Sora did NOT slash at Xemnas as they pass in one of the possible scenarios triggered by the reaction commands. Gameplay mechanics, probably, but I might just look a bit deeper. Definitely it's not like a Riku/Roxas situation, since both are armed, fully ready to hit each other, and their eyes threw daggers at each other as they zoomed by each other.
They were both enemies. Even if Xemnas had not slashed down on Sora, Sora would have hit him. It's hard to think why they wouldn't do so.
But as can be seen through all the reaction commands available, when anyone actually hit, it was always Sora who took the first move until it became too late, then Xemnas thrashed Sora. Which was quite long after all the possible chances that he could have swung out with his lightsabers and decapacitated Sora. Even if it was in an illusion and all, nothing would actually have happened, though.
This leads me to believe that the hesitation shows that Xemnas did not want to actually hurt Sora in there unless as a last resort. Time was bought and he did not strike Sora when he had the chance, until it was practically too late.
Thus, it goes to show that there was something about that memory of Deep Dive that Xemnas actually wished to recreate in such a scenario. So why would he want to recreate a scenario of Deep Dive?
Once again, it leads back to the possibility that he may wish to awaken Ven. There is probably a much greater chance of it occuring in a situation similar to hypothesis 3 listed above when Ven and Xehanort were also engaged in a similar combat situation. Because by connecting as many similarities as possible to that battle, the chances of awakening may have increased.
But probably as a gameplay mechanic, or maybe Xemnas just didn't want Sora suspicious about why he gave such a big opening, he just cuts down on Sora after about 10 seconds of doing nothing.
Thus, if we see hypothesis 3 through, we can see that All Roads Lead to Ven. Hypothesis 2 of the battle occuring so that Xemnas could get Roxas on his side is dispelled largely because he would need to manually pull Roxas out by turning Sora into a heartless.
Do note that this is really all a hypothesis based theory, so I hope you people will look at it and give me some opinions.
Significance of Deep Dive 
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