Poor Han! Naturally he don't know anything about the complex relationship between a chiropteran queen and her chevalier, even if Saya told him in this regards. (I think I felt really sorry for him.) Howsoever, I hope this incident don't fade his resolve to discover some scientific technique able to suppress or, at least, to minimize the hibernation cycle of the chiropteran queen - if not for love, at least for mercy.
Lona and Alan of the Han's scientific team, remind me, respectively, Julia Silverstein and Aston Collins of Red Shield (it's no coincidence, right?); by the way, except for the "fifth base" theory for the mechanism of the chiropteran metamorphosis (or "transmorphosis"), very little was discovered about the chiropteran biology and the origins of (I think we might name its) "Chiropteranthropus Genus". On the other hand, seeing Han immerse himself in the reading antique, pristine voluminous books (pile of paper), redarding the mythical vampire-like creatures, remind me one scene in my own fanfic, where Abraham Souzanitzky is doing similar activity, because he wants to unveil the secret of the Saya's true nature.
The return of Saya is a grateful surprise - or not? After all, she sounds more vampire, more bloodthirsty than ever. Apparently, even Han is beginning to be afraid of hers.

The protective attitude of James to his Master Han reminds me similar (almost parental) attitude of Bruce Wayne's butler, Alfred; was Alfred the model and inspiration for James?
I enjoyed your "transformable" aerocars (would they be antigravity airships?); it is a fascinant and elegant combination of tradition and futuristic technology, which only could be found on the planet Earth, "Old Earth", homeland of the Humanity.
Despite the James' fears, the romantic relationship of Han and Saya is booming. Neither Solomon nor Kai were so lucky - not even Hagi, I think (Oh, how jealous!). However, seems like Saya accepted her vampiric nature, as a blood drinker (real or synthetic blood); and Han also took it on in good standing, and even the waiters - something that would have been inconceivable just centuries ago. How much the Humanity evolved, right?
To say the truth, in my own fanfic, my O.C. (Abraham Souzanitzky, my fictitious alter ego), also begins a kind of romantic relationship with a more closed herself version of Saya (similar to what she was from 34th to 38th episodes, or as Saya Kisaragi in "Blood-C the Last Dark"). Despite the differences between your story and mine, there are many contact points, similar situations. I believe that it has been due to our love by Saya.
However, I think my Abraham has a vantage point over your Han: Hagi don't exist in my story! (laugh)

Hmmm... It would appear to me that there's a chemistry between Saya and "master Han". So is there going to something romantic happening between both of them?

So I guess Saya was awakened in the 28th or 29th century of the Gregorian calendar, right? Thus, the "Great Exodus" happened for the mid-26th century. By the way, I would like to know if the Humans have ever discovered other civilizations or alien races across the Galaxy. (Would be aliens the chiropterans?)
OBS.: pardon, but the correct term is "chiropteran", isn't "corrupteron".
Sincerelly, I'm surprised that Saya is blend with Han so rapidly, so intensely; is it a sign of her affective lack? After all, she lose her human family, her chevalier, her nieces (what happened to the Diva's daughters?). Perhaps beacuse of this, Saya is getting attached to Han. On the other hand, he is perceptibly fascinated/attracted to Saya. I think there's something (romantic) brewing between them...

This is a very interesting beginning - there is something new in the Blood fanfictions. By the way, Han (your fictitious alter ego) and James (is he a real human being or an android/replicant?) remind me of the duo of scientists Joel and Amschel Goldschmidt, which discovered the mummified chiropteran mother of Saya and Diva (with their cocoons in her womb). I also began to write a Blood fanfic, titled "Saia do Casulo!", in Portuguese, my native language, whose main co-protagonist is my own fictitious alter ego. Because I also was in (platonic?) love with Saya. Hence my self-insertion in my fanfic.
The suggested background to the far future is intriguing, because there are virtual and/or biological immortality for the human beings, interstellar transport and colonization, while the homeland planet of the human race appears caught in a time warp, a type of hinterland.
I'm looking forward to watching the interaction between your O.C. and newly awakened Saya. For a first chapter, it is very very good.

Poor Saya .if are planning to right any other blood stories let me now got few idea's and Oc's that you might like.