Look at me, the  kh13 user who won't shut up. I have never come up with so many theories before. 

 

According to Nomura, that guardian of Terranort and Xehanort’s Heartless is NOT a Heartless. So, what the heck is it? Take a look at Xehanort’s Keyblade (for technical reasons I cannot post pics here so if you don't mind just...look up the pics. So sorry  

 

Many people have theorized this originally belonged to the mysterious Sixth Foreteller, as it bears a striking resemblance to the other Foreteller’s Keyblades, and with the new Kingdom Hearts III trailer, the theory is growing more and more likely. Now, going with this theory, it begs the question: are there any side effects of wielding this Keyblade? 

 

Take a look at the Guardian. After you’ve done so, perhaps you see there’s a sort of resemblance between the Guardian and this Keyblade? And the Guardian has an X on it’s body, and in this series, anything with an X in it, be it a name or clothes, is serious business. 

 

What if through using this Keyblade, Xehanort is enabled with the use of the Guardian, who is a manifestation of the Sixth Foreteller. The use of this Keyblade affected his Heart, which is why when Riku used Xehanort’s Heartless powers, he was able to use the Guardian as well. 

Edited August 7, 201510 yr by Salve-SiS

nice theory, but xemnas and no heart never used the guardian and riku and ansem never had the keyblade, plus we never see old xehanort or young xehanort use the guardian.

nice theory, but xemnas and no heart never used the guardian and riku and ansem never had the keyblade, plus we never see old xehanort or young xehanort use the guardian.

Young Nort most likely doesn't have it yet. The Guardian just for some reason hasn't showed up with old nort. It proably only comes out when it wants to.

Young Nort most likely doesn't have it yet. The Guardian just for some reason hasn't showed up with old nort. It proably only comes out when it wants to.

what about riku and no heart, plus terranort, ansem, and riku summoned it on command

what about riku and no heart, plus terranort, ansem, and riku summoned it on command

 

Well a possible explanation is because using that Keyblade touched Xehanort's Heart so that it gifted him with the ability to use the Guardian. Remember Ansem gave Young Xehanort the ability to time travel? Something similar to that could have occurred with the Sixth Foreteller and Xehanort...somehow.  

I always just figured that it was a manifestation of ansem's/terranort's dark power. Kinda like a susanoo is in naruto (if anyone has seen or read naruto)

Maybe the guardian is the spirit of the Master Foreteller. Xehanort himself said that his Keyblade is the most ancient of his time, so, it inevitably makes sense (presuming his Ram Keyblade is indeed the master foreteller's and not the sixth forteller's) that his mind may continue within the Keyblade.

Interesting theory. Now after reading it I've thought of my own theory, what if the Gaurdian isn't a reflection of the Sixth Foreteller but rather a "spirit" of some sort that corresponds to a foreteller. You mentioned that Guardian resembles MX's Keyblade so what if each Foreteller had its own gaurdian. For example, Vulpeus' "Gaurdian" would resemble a fox, Ursus' would resemble a bear and etc. Thus Ansem and Terra-Xehanort could use Gaurdian because they maintain Xehanort's essence, who wields the Sixth Foretellers keyblade. However I think this is unlikely (but would be cool) because wewe've never seen MX using a Gaurdian before possessing Terra (nor do we see Xemnas do so either) so I still think that its momore likely for the Gaurdian to connect to Terra or Eraqus as many have said.

 

Also may I ask when did Nomura say Gaurdian was a heartless (like the Interview or what not) Thanks!