I said I'm assuming that the basement visit happens before KH2, considering that your already there at the beginning of the game.
I know its all based on pure speculation, but 1,3,4, and 5 are all facts. We all assume 2, there is no proof that it is in fact Aqua, we just assume it.
If I were to theorize this it would have to be like this;
**Chronological Order of Events**
-The time of Terra, Ven, and Aqua and of MX and DS, respectively
-The break out war between the 2 sides
-KH1
-CoM
-We assume that this is around the time of the basement visit, considering that Radiant Garden was visited by Sora at the beginning of KH2 and the castle infiltration soon after. I highly doubt Xemnas risked going there after Sora visits in the beginning, and returned anytime there after.
-358/2
-KH2
(The meeting between Roxas and Xemnas could've happened anytime from the ending of KH1 and the beginning of KH2.)
(I'm not to sure where to place Coded in this. I don't see that event as important to my theory though.)
*Summarized Theory*
War happens between Terra Ven Aqua against MX and DS.
KH1
Sephiroths boss battle is a biznatch
yayy we saved the princesses
yayy we defeated Ansem
yayy we get sucked into a dark oblivion of light that takes us to a similar crossroads like in the Sunset Horizons video.
CoM
yayy Riku is alive and well and so is the King
yayy Axel
yayy Zexion
-Assume that Xemnas has visited Roxas at that location and told him about the person who looks like him.
-Assume that the basement visit happens
-Assume that its Aqua on the floor
-Assume that while thinking of his past, Xemnas remembers everything, goes to a place of child hood, sees a tired frozen, dead Ven as a monument as a hero for defeating the darkness, mass confusion occurs in Xemnas mind, he visits Aqua and talks to her for several hours about her past triggering the mass confusion to come back and make Xemnas remember something, his precious memory comes back to him and he becomes an emotional being.
-Now assume that the reason he wanted to tell Roxas or mention it to Roxas is cause Roxas' non existent heart is the only thing that can free Ven from his ice traps, and also assume that the reason he wanted to defeat Sora wasn't for KHs but so he himself can unlock Ven.
358/2 days
(no comments)
KH2
yayy Axel, again
yayy we play as Riku
EDIT:
lol, Xemnas was refering to Sora...
Nomura himself said that the scene where Xemnas was talking to Roxas was almost directly after the battle with him in FM...
I have 2 problems with that.
1) That extra boss battle shouldn't count as an actual meeting cause isn't it an optional boss battle? You didn't have to do it right?
2) Nomura also said that the 3 characters (Ven, Aqua, and Terra) are all new characters with 1 only having a connection to previous characters, he himself stated that all 3 have a big impact cause of element denomination.
Sora - Ven
Riku - Terra
Kairi - Aqua
I'm not saying i agree with the fact that the referral was to Ven, but I'm just stating my thoughts on why it could be he was referring to Ven.