.

I copied pasted this frpm someone's post:
Nea (the 14th) is taking over Allen. The current millennium earl is mana, nea's twin brother. He is also the same mana that allen spent time with when he was a kid. Mana and nea are both the millennium earl.

However the Millennium Earl turned Mana into an akuma didn't he? That's how Alan got his cursed eye right?
How can Mana be in the same place twice and how can he turn himself into an akuma without even realising? Was that even Mana Alan spent those years with?
Who died then?
This is the one thing I don't get.
Maybe Nea is just mad...?

Or maybe the tramatized Allen was confused and
his memories about how Mana died are not real.
He's possesed after all by the 14th/Nea.
Maybe in that incedent itself was when Mana killed Nea and Nea possesed Allen as a curse in his eye.

It could very well be so, but that might feel like a bit of a cop out, I don't know, depends on how it's presented.

I don't quite understand what you're saying here, sorry :( But if you mean the incident where Nea was properly killed then that happened years before Allen and Mana even met. I think 45 years ago but I'm likely making that up. So it can't of been Nea's death and possession of Allen that gave him the cursed eye.
I think Allen was already a host for Nea when he met Mana, since Nea had told Cross to specifically look out for someone, that's too much of a gamble to risk his entire scheme on if he hadn't already known Mana would be approached. Also, and again it's been a while so I could be making this up, but I think we say Allen in one of Nea's flashbacks saying he'll be host? So yeah, I think Allen has been the host for a while now.

I don't really remember where Cross was during the time of Mana's death and the events that followed but he was mainly meant to be watching over them right? So we can't really expect that different a time-frame than Allen's memories of the incident otherwise Cross would know it, if that makes sense. I think he also claims to Mother that Allen turned Mana into an Akuma but again... memories... Cross is the one that recovered Allen and brought him to Mother so if anyone would know it's him. Though Cross has certainly not given all his secrets away so who knows how much we can trust his word. Though if he mentioned a story similar to Allen's to Mother I see no reason he'd lie since she already knows a lot of what's going on and she's not really going to have that much of an influence over events.
I hope I make sense, I don't have time to go research my facts right now but here's what I remember ^^

Hey :)
I might as well re-read the whole manga again to get a clue or a hint.
All we can do now is speculate.

Very true :)

Just gotta say. Mana and Nea are not twin brothers, they two parts of a whole(the millenium earl).

That is if the whole 'they're both the Millenium Earl' thing is true, which was what I had a problem with :)
But who knows, sensei will probably surprise me.
But yes, you're right. Technically right now they're the Millenium Earl split in two.