Ok, so BBS hasn't even been released in America or Europe (where I live - England). But I'm confused, the only secret boss I have seen is Lingering Sentiment Vanitas... I've seen the Terranort fight on Youtube but Nomura said that neither of these bosses are THE secret boss... Mirage Arena is just a place, Terranort = final boss and Vanitas LS is supposedly like Kurt Zisa in KHI... So who's the Terra/Sephiroth (KH2 examples) of BBS?

When did Nomura say neither Ls Vanitas or Terranort is/are the secret boss?

I remember reading it somewhere, I thought like everyone else that LS Vanitas is the secret boss... maybe it was unconfirmed.

well sometimes articles can be wrong but hmm that seems weird uh maybe u have to finish all worlds stuff?

LS Vanitas is the secret boss, he totally fits Nomura's description: 'One HP-bar, but stronger than any boss you've fought against so far.'

And that's quite him.

 

But what I'm interested in is the other boss Nomura spoke of, the one in Mirage Arena which, so Nomura states, would be even harder to beat, especially when not being in Multiplayer mode.

Haven't seen anything on Youtube yet, not even a picture.

^Iron Prisoner. You fight him 4 times throughout different Mirage Arena fights. Nothing secret about him, he's just hard to fight on your own.