First off, the ones that aren't Simply rumors.
While in Korea, we've had book 19 for a year now, America is slowly catching up.
Due to an illness, Mr. Lee had to put a temporary hold on his creation, REBIRTH.
He's been back at the 'drawing board' as is said now, and has been for several months now.

We're in high hopes that Volume #20 will be out within this year.
And in the mean time, it gives Tokyopop a chance to catch up in it's translating current books.

Also, speaking on translations.  A long time ago, I contacted Tokyopop;
it was due to the fact that in the American books, Deshwitat was actually given two different last names.
In the beginning it was Deshwitat Rudbich, but then it had changed to Deshwitat Ludbich. 
At the time, I knew no Korean myself, and desperately wished to know WHICH was the correct name.

Turns out, he is one Deshwitat Lived Rudbich. 
I did receive the editors' appaulogy, and assurancethat he wouldn't let this mess up happen again.
And as I started learning Hangul, I found out, that you use the same symbol for the 'L' as well as the 'R'.
Hence?  Easy mistake.  So there ends another grand mystery. ;)

As for the other mysteries???
Well then, many of us believe that Grey belongs to none other than....
Deshwitat and Lilith.
Sure, he calls Kalutika father, but that doesn't mean a lot.  Grey IS a vampyre, and he DOES belong to Lilith,
and Kalutika finds it VERY amusing the thought of Desh and Grey fighting one another.
So?  Yeah, I'm in the belief that Grey definitely belongs to one Mr. Deshwitat L. Rudbich.
Confirmed?  No, not yet, but here's to hopin! :)

The Robed Man.
Aside from the great Kalutika in another 'dimension/whatever',
I haven't the Faintest idea.  So sorry.  Why do I think Kal?  Just and Only because of his lips.
Kal, while Absolutely beautiful, he does have about womens' lips.  And so does the 'Robed Man'.
Also, to those who say,why would he allow for such bad things to happen to his younger self?  He would,
because that is what it took for him to break free.To become the powerful creature that he now is.
Do I believe that Kalutika IS the 'Robed Man'?
Somewhat.  Positive?  Never!!

Lastly, in book #18 where Deshwitat and Millenear are facing off, Grey sits to have a 'chat' with Deshwitat's bunch.
No one's thrilled by his appearance there, but then Grey starts speaking of Mill and her 'True Identity'.  He's not talking
about her being in love with Deshwitat or anything of the such.  He says something along the lines of in her death, she'll be reborn?
--(Please forgive the trans. as Korean is not  my native tongue, and is actually quite hard to master on ones' own).  And that in
every posible existence/future, hers is one of great importance.  Enormous.  He also goes on to speak of when she was excommunicated
as well, and of her (Mill) desire to possess Deshwitat. 
So?  What does all this mean?  I believe it has to with Grey's report to Kalutika a while back.  When he told him he might have something
on the possibility of a 'harvest' of these so-called godseeds.  That report came just after his meeting with Desh, and he had Millenear.
I think there's a slight possibility that Millenear is one of the godseeds.  No, she wasn't all that strong before she got vamped out, but then
again, neither was Kalutika.  The true power came after he 'died'.  And while Grey admitted to giving Mill extra power "It's the least I could
do.", Grey is NOT the one who turned Millenear--that was Rang.  As soon as Rang changed her (as you see in #19), a great blast power came,
and then (with Grey getting upset) Millenear sat up and was what she is now.  Plus!  There's the fact that she shouldn't be able to use her
powers at all.  Now that she is, as Deshwitat put it, 'One of the damned'.  While it atrophies her arms/hands terribly, she canNot heal that
on her own, and needs Grey to do this for her.  Deshwitat said it should kill her, but it doesn't.  Sounds like what Grey said is true, she's
certainly 'More than meets the eye'.  Guess we'll just have to wait and see.

Newest one!!  Millenear Shephild!  WHAT is she??  According to book 18 (think it's 18), when she's fighting Deshwitat in the VLT, Grey
speaks with Rett and crew; and reveals that Millenear is 'More than she seems', says she's not what everyone thinks she is.
Ok,roughly (haha- translated by cha/me):
Her future (in any of them) is enormous.  But that she falls in each (or falls short?).
And then Grey was talking about her (Mills') 'True Identity'
To which he mentions about it being complicated.
All in all, he's talking about both her past of being excommunicated and her future, of what she is to become (or should have).

So what's this all mean?  Ok, ONE possibility, is that she is/or could be, the next g'dseed.  Why?  Well, Kalutika was already told that there
was another g'dseed on Earth by the so-called g'ds.  And Grey, in his report to his 'father' Kalutika, said that he would have something next to
report on a possible harvest of the godseed(s) next time.