Why isn't nathan dead??

"In the light novels, it is suggested that the real Nathan Mahler was tracked down and killed by the chevalier of Saya and Diva's mother, who then transformed himself to pose as Nathan and replace him as Diva's chevalier."

In one episode, Nathan told a story about how a servant couldn't protect their queen:

Nathan: The world exists as a shining stage for Diva so she can be adored. It was proclaimed even before Diva was born.

Amshel: You talk like you've witnessed it.

Nathan: Actually, I did.

Amshel: Hmm?

Nathan: Years ago, there was Saya and Diva and the mummy that was their mother. What she had then was a faithful chevalier just like her daughter today.

He kinda alluded to the fact that he is Saya && Diva's mother's chevalier. "Since Nathan is far more interested in Diva than Saya, and speaks of "History repeating itself", it may be presumed that the queen he originally served was the blue-eyed twin."

I think Nathan wanted to just disappear really, there was no reason he had for living after Diva died. I think he KNEW Saya's blood wouldn't kill him.

And it was way more than a feeling xD he proved it multiple times, he is stronger than ANY of the other chevaliers. "Nathan's exact powers are unclear. He can either move so fast that he cannot be seen with the naked eye, or he can change his form to trick others into not being able to see him. He also appears to have a form of telekinesis stronger than the other chevaliers, seemingly able to shatter glass with his voice."

It would make more sense if Nathan was their mother's chevalier rather than their aunts because saya and diva got their mother's blood ((right?)) so going on the anime's logic, than Nathan would have died because he "has" the aunt's blood.

What I wanna know is why the mother looked like the other chyropterans yet ((if nathan rly is her chevalier)) nathan is human like. can the Queens shapeshift? o_o Diva never did and she seemed more likely to shapeshift than Saya ever would.

And what could have happened to this aunt? I'm thinking she killed her sister and maybe Nathan killed her?Or she died, or she could be "sleeping."

What REALLY bothered me was, the queens stay awake for about 2 years right? and sleep for 30. Well in the flashbacks, haji came to the mansion....and grew up...yet saya never slept o.e Was there something i missed or was haji already like 18 wen he came haha he looked like he was 10 or so, really.

Oh I think I figured out when they sleep, I think they start to hibernate when they get their first chevalier ^^; lol anyone else have another explanation?

And by shapeshifting I meant like into the Chiropteran form. Because it seems like Diva would use it to get alittle more power or something but she never does. So idk I was just wondering if they even can and why the mother was in the Chirpopteran form when she was a mummy.