I have a solid theory on why Terra is in the RoD

[Joker 1,560]

Remember in Kingdom Hearts 2 when Xigbar mentions while Xemnas is in the room of repose, he can hear two voices? And the fact that he seems to be talking to Aquas armor. What If the other voice is Aqua. Some how in that room he can talk to Aqua and go to the world of darkness.

 

It puts even more a solid fact that it could be Terra in control of Xemnas. It is said that Xemnas can use a keyblade but doesn't. What if the fact that Terra is in control means that Terras keyblade will appear. Also when Sora is giving hos speech to Xemns in DDD Xemnas seems to be happy about it. What if this is Terra who is in fact happy that Sora now knows the Truth but also he has to keep pretending to be sided with Xemnas.

Edited June 12, 2016 by Big Boss

[Robbie the Wise 5,050]

Only problem is that DDD has firmly solidified that Master Xehanort has always been in control, and all of his other selves were following his designs(As cheapening as that is to those characters). I don't think Terra is really in the Realm of Darkness, I think Aqua's memories have been manifesting themselves. In that scene Aqua was reminiscing about being with her friends, then she says "I'm doing it again". Then directly after Terra appears in almost the exact same fashion he did the last time the two of them were in the Castle of Dreams(During BBS). As I've said in another thread, we've seen this before. In DDD the deeper Sora dove into the darkness the more of his buried memories were able to manifest. Xion, Ventus, Terra, Aqua; all those memories manifesting themselves in the further Sora sunk into darkness. It's like Ansem said "Dreams holds our memories, sleep holds our dreams, and darkness it holds our sleep".

[Kaweebo 3,617]

Well, you had me until the 'Terra is in control' part. I do think the idea of Xemnas attempting to communicate with Aqua through her armor and appearing as a vision of Terra is an interesting concept, only under bad circumstances. Xemnas is using Terra's heart to reach Aqua and of course, Aqua would see him as she remembers him. 

 

While I don't think that's the case, it would make his appearance in the RoD a lot more sinister than just a simple hallucination. 

[The Transcendent Key 12,109]

While this is an interesting theory, it's like Robbie said.  Xehanort has been in control all along, so Terra has no control over himself, though he may try as hard as he can, ya know?

 

I firmly believe that Terra in the Realm Of Darkness is just a figment of Aqua's mind.  A hallucination.  Poor girl has to fight the insanity that's getting to her!

[Headphone Jack 1,147]

the Terra in the RoD is probably a memory from Aqua.

 

maybe she's experiencing some de'ja vu from being in the Castle of Dreams again.

Edited June 12, 2016 by Headphone Jack

[Axtwyt 500]

Remember in Kingdom Hearts 2 when Xigbar mentions while Xemnas is in the room of repose, he can hear two voices? And the fact that he seems to be talking to Aquas armor. What If the other voice is Aqua. Some how in that room he can talk to Aqua and go to the world of darkness.

No duh. We had this figured out when Birth by Sleep came out.

[OmegaForte 1,674]

Pretty sure it's the RoD messing with her memories. I mean the beginning of the trailer already has Aqua strongly hinting at this by what she said.

[King_Graham 135]

It's either a remnant of the worlds dream seeping into reality or, more likely, the RoD itself messing with her memory.

Edited June 12, 2016 by Andrew Rowland