Well i just noticed this are several others probably did too. Take a look at these photos very carefully, okay so you can't really see the images but this was close to what I could find. Terra's armor is different, yeah obvious but hear me out. There is more that the eye can see. Terra's Keyblade Ends Of The Earth has no keychain in Kingdom Hearts 2 , but in Kingdom Hearts Birth By Sleep there actually is. At first, I was like wait am I imagining things? but the secret video did not include it as well. So I never knew why. My first thought was, oops mistakes in the series, but then I noticed something else. His armor looked bigger in Kingdom Hearts 2, and including the cape that was not proven yet but i saw a video about 2.5 that showed in Birth by sleep Terra's cape magically came out of nowhere. PROVEN! but that does not explain where his keychain went, and that black part of his neck does not show out as much, and his wielding stance is a little different.  Also his armor is a little darker. So basically the keychain to Ends Of The Earth is missing, if anyone can sum it up for me then thank you and some parts are missing and added, look closely. So yeah, thats it.

Terra's (and Aqua's and Ventus') designs weren't finalized when Final Mix came out. I imagine they could have changed it now to fix that, but Terra in KH2 has a lot of animations, and very complex animations. It probably wasn't worth the time it would take to change all of these details, especially for a secret boss most players wouldn't even reach

He lacks a keychain cause at that time nomura didn't have designs for it. Also the rest is pretty obvious

Edited October 25, 201410 yr by kurasa25

That's because Terra, Aqua and Ventus were meant to carry only one single Keyblade and 10 years back then keychains weren't really necessary.

Maybe he didn't find time to take off the keychain while fighting Xehanort and then he took it off after it, which explains why it wasn't there when he fought Sora.

Maybe the keychain rusted away, or maybe somebody stole it.

Edited October 26, 201410 yr by mvitkun

Maybe the keychain rusted away, or maybe somebody stole it.

I was literally just about to suggest this haha.

That's because Terra, Aqua and Ventus were meant to carry only one single Keyblade and 10 years back then keychains weren't really necessary.

But Terra's keyblade had one. I thought because it was gone, it was passed on to Riku.

Yeah, it's just because Nomura hadn't finalized the designs yet. Nothing special, and no errors involved.