We know the secret boss of any game is related to the major plot in the next one right?

KHfm--Xemnas

KHIIfm+--Lingering Sentiment

So I was reviewing the e3 trailer on birth by sleep. My attention was caught on the design of he new secret boss

The last interview revealed that, like the Lingering Sentiment, this mystery boss exists during that time period, but it makes no sense that he would be in that particular location at that time.

 

The being known as Apprentice Xehanort hasn't been born yet; rather, it's still just Terranort. Saying it's AX would imply that this takes place after BBS, and Aqua has already fallen into the Realm of Darkness by that time. Asides from that, he would have no way of getting to the Land of Departure of all places, especially considering he lost his memories. It wouldn't make sense for him to just suddenly be there and randomly challenge a person he doesn't even know to a battle.

It pretty much depends when you fight the secret boss.

there has to be a thread like this some where,

 

anyways, reversal makes a good point, all that is true, and most likely that character will not be known until the next big title game (the secret boss of kh1 fm was revealed in kh2, a main title, and the secret bos of kh2fm was revealed in bbs, another main title, so we can assume that this person might be revealed in kh3, but that is just a theory, i can't say for certain)

http://kh13.com/mybb/showthread.php?tid=6949&page=7