Balthasar von Neumann and Helga von Vogelweide are the people from the novel,"Trinity Blood Rage against the Moons".
Unfortunately, they don't appear in the anime, manga, or the another side of the novel ("Reborn on the Mars").
If you want to know the exact things about them,
I recommend you to read R.A.M.4 to 6. They are "Judgment Day", "Bird Cage", and "Apocalypse Now".
Oops..., are the latter part of the novel not published or translated in English yet?
Then, if you have some ability to read Japanese, I strongly suggest you to try them!

Disclaimer:

Of course, I don't have the rights to own the characters.
They're definitely the creations of Sunao Yoshida (May his soul rest in peace...)

In the same way, the composer of the waltz "An der schönen, blauen Donau"
(In English, I suppose it's called "The Blue Danube" or "On the Beautiful Blue Danube")
is, Johann Strauss the second. He was an Austrian composer, as you know.

In addition, "The High Altitude platform" is a quasi-stationary aircraft. It's a plan of science, and there's no concern with me.
The possibility of building this structure is still in theory, and it remains incomplete and been regarded as a SF-thing.
If you need more info, take a look at wiki in article of "The High Altitude platform" or read the novel R.A.M.6, "Apocalypse Now".

Die kalte Eisblume schneidet scharf.

Chapter1:

A.D.3011---An der schönen, blauen Donau

In the middle part of the Europe, there was a historic city called Vienna in Dukedom Ostmark.
Usually in Roman Common Language we called it "Vienna", but in original language which the people living there used to speak, it could be "Wien". This metropolis was famous for its tendency to cultivate classical music.
With its strong pride of being a homeland of numerous composers, the city had become headquarters of many authoritative musical society for long years. The systematized pride tended to grow the intelligentsia, the privileged class, and the nobility. The distinction of classes might do some wrong for one side, but spontaneouly for the other side, it could produce some kind of beauty. And the scenery an altitude of 2,000 meters above there was absolutely beautiful.
One classical waltz called "the Blue Danube" would be well-matched with this sight.
Just like the music progressed, the river Danube was flowing through.

The original source of this river existed in Donaueschingen, the old city of Kingdom Germanicus.
There the flow of the water was given birth into the world, and then began to make its way.
Going through the gloomy Schwarzwald and the many deep forests, the river went by people's dwellings.
It visited many nice towns and cities, such as Ulm, Ingolstadt, Regensburg, and Linz.
After passing them, the Danube finally arrived in the city of Vienna.
From the dark beginning to the bright cities, the river kept on flowing.
People would be surrendered by both the world-famous waltz and the wonderful creation of the nature.
Wandering the colors between azure and blue, the flow constantly kept on going, and gradually began to slow down.
It's just like a miniature of life. The more beauty it had, the more solitude it would include.
Indeed, the graceful flow was worth looking for a while.

But in fact, this view of the Danube high up from the sky was something only a few people were allowed to look at.
From the entire citizen in Vienna, only three brothers who belonged to Methuselah were able to see a bird's-eye view of this city.

The Methuselahs had apparently no difference from the human being. But they were clearly different in some ways.
First, they had much more quicker reflexes than human had. And they had very long lives, such as Methuselah the son of Enoch in Genesis.
Second, they customarily needed the blood of human, in order to continue their lives.
Third, their fear for the sun was so much. Whenever they felt the touch of the sunshine, terribly they suffered.
Fourth, they called themselves "Methuselah" proudly, while they contemptibly called the human"Terran".

And this place, a few thousands meters above the city of Vienna, was called "The High Altitude Platform".
Long ago this facility was used as the radio-relay station covering a wide range, but now that things had come to this pass.
Leaving some of the equipments behind, most part of this place had been reduced to ruin.
Thanks to the solar power generation, the facility itself kept on floating in high air near the stratosphere.
But the inner machines used for wireless communications were critically damaged.
In a word, this ruin was just an empty place. There was nothing worth watching except for the scenery.

But some people, the distant descendants of the founder, were still looking after this ruin.
That's why this place had been saved from a perfect devastation.
The administrators of here were three brothers of Methuselah. And now among three, only one person was here.
The eldest of them, seemingly a young man with an elegant looks, was looking down the outer world through the anti-UV protected windows.
There was no light in his eyes, and he seemed not to focus his mind on something special.

He was indeed good-looking, but his figure looked like a lifeless sculpture rather than a living thing.
No expression was appeared on his face, much less the feelings.
Blowing his medium hair in the soft air, he was vacantly taking a look at the scenery.

***

The streetlamps and the gas lamps are the artificial lights which work some electricity or some scientifically-processed gas.
At the time of twilight when the natural sunlight is fading, especially they look glaring for me. They're too bright to see in the near position.
But in this faraway place, they get easier to look at. I can say it's simply beautiful, even though they're the products of the Terrans.
The light of Vienna overlooking from here have some resemblance to their producers.

The Terrans are the species which have less technology and less knowledge than us.
I take it for granted and have no doubt they will be conquered by our side someday. It is true and strategic fact.
On the other hand, another fact exists. It may be contrary to former fact, but I've noticed it.
Another fact, that the Terrans have more vitality than us, is also true.
Looking them one by one, they're weak indeed. But as a group, they can make the violence of the number.
And make it possible to threaten the Methuselahs...What annoying species they are! They should be damned in the near future.

However, I know the reason why the empire of Methuselah keeps them alive.
In exchange for huge money in a suitable manner, the empire collects the blood of the Terrans.
The blood productive medicine is made from that, and we utilize them as supplementary nutrition.
It's supplementary for our meal, but essential for us to live.
And from that medicine, we get "Aqua Vitae"-—the water of life. Simply speaking, it's just blood.

The Terrans, are weak and powerless species.
But they know the short-term of their lives well, and struggle to improve the cultures and the ways of living.
The mentality of them is difficult for us to understand. Why they stick to the lives, against the natural-born DNA?
We're destined to live a few hundred years long, and the Terrans are doomed to live with the fragile bodies.
Why are they trying to change that?
A desire for the long life, or the anti-aging? I have no idea about it. Perhaps they don't understand themselves, either.
In addition, they don't know the weariness within the long life.

The question or anxiety about invasion from Terran-side is still not becoming a problem.
As a matter of fact, I think we should warn. At least we ought to take care of the possibility what to come.
In the daily life and a short span, we need not to think about it.
But in case of a long span, the thing and the situations may change some more and some less.
I've noticed this idea through the observation of the current reality. The conservative ones cannot hold the future.
Even though they've got plenty of knowledge and high abilities, the future will be limited or entirely meaningless.

For example, how about three brothers who are just performing the task inherited from their ancestor?
What kind of future will they gain?
Maybe nothing. Nothing at all. I'm sure what lies beyond our time will be vacant...

***

On the handsome face of brown-haired young man, a strange expression appeared.
It seemed as if he was laughing a little. He made laugh at himself, drew ridicule upon nothing but himself.
However, the bitter faint smile ended instantly.
And at the same time with very good timing, the classical music which had been playing here, ended also.
Then this high-airtight room was reigned by an intolerable silence.

Silence was nothing. Nothing could be heard in this room.
But an excessive silent situation occasionally indicated some facts. The facts were so strange that he was hardly able to recognize it.
What were they? They were about dominion of this room, place, and an artifact which the ancient Methuselahs had created.
Covered by the deadly silence, his justifiable right to dominate here seemed to be lost.
At the moment, the long history included in this place became dominant.

And he, the aged Methuselah with the young looks of a person in his twenties, seemed to become one part of the history and the silence.
This deep silence would last for a long time, till his brothers returned here.
Even though they had returned, the solitude and the painful void might not change at all.

The second brother, Melchior, hadn't talked to him for ages.
He had completely lost the interest in living thing, and concentrated on making dolls.
The dolls which exactly meant Automatons were anyway well-made,
but absorbed only on one thing was not proper for a person to communicate with someone.
The situation was almost same about Kaspar, the third brother.
The youngest of the brothers had a cheerful character, but on the other hand, he'd got a perversion in sexuality.
And so he tended to leave their sophisticated home, and preferred going to the downtown.

As if they had lost their purposes to live, they had been killing and wasting their times.
There was nothing that stimulated them. Only the duty to control this ruin was upon them.
The unpleasant events hadn't been waiting, but also anything special didn't come over.
Thus the three brothers of Methuselah had been living.
The second brother was a half-mad scientist, and the third was an epicure.
And this man, who was standing in front of the windows, was the eldest of them. He was a kind of nihilist and a man of agnosticism.

Probably today would be the usual day. Without any strange thingor accident, the sun was straightly beginning to set westward.
Soon it would be the nighttime and then there would be no fear for the Methuselah to live.
The night was their time and the day was for the others.
If it were not for the sunshine, there would be no need for them to annoy.
Only the weapons made of silver and the sunshine were their weak points. About the other things, they could defeat everything.

Seeing the sun set down beyond the horizon, the brown-haired Methuselah looked back and started to leave this room.
It was a soundless action, and here was the very silent place.
But just then he went a few steps forward, he perceived an unusual sound---the heartbeat of someone.
Someone who didn't himself. In addition to this faint noise, he heard a sound of footsteps.

Could those be the sound made by his brothers? No, it couldn't be true.
At that time they'd been to the city and it would take a few days for them to return here.
Next, a disagreeable burglar's visit came into question. Would there be some possibilities of entering someone unlawfully?
But it was almost impossible. The surveillance network and guarding system of this facility had still been working perfectly.
The entrance couldn't be come through without self-identification,
and the certification of this place was allowed only three brothers who were serving as the administrators.
Moreover, the passwords were changing hourly in the very important place such as the main controlling room.
Whoever tried to enter the room was needed a long and complicated words.
And above all, before everything else, the facility itself existed in a place where an average person couldn't reach.
It existed far up in the sky, near to the stratosphere.

Doubting the mistake of his ears, the Methuselah began to walk quietly in search of the sound.
His speed of walking was a little bit slow pace, just like walking in the forest for a personal relaxation.
He didn't have to be hurry or afraid, because the surveillance network set all over the facility wouldn't act toward him.
It's natural and no strange. The DNA-information of his family was registered as the administrator of this place.
No alarm sound or warning would surround him.

But in this case, there were some reasons except for the proper reason.
The surveillance network didn't work active for the legitimacy of his DNA,
but because the optical and infrared sensors on the way were destroyed by someone.
It was utterly destroyed not by physical violence, but by a more complicated way.
They had been broken by the data-cracking virus sent into the inner control units.
The highly efficient machines created by the ancient Methuselahs were mostly made powerless.

What the Methuselah saw in his presence, was the abnormal sight that he had never seen like that.
As a matter of course, his suspicion was on the increase. Who on earth did come here? What is he or she plotting?
Considering the questions and their possible answers, he got closer to the source of the sound.
After passing by a quiet corridor, he finally found the target he had been looking for.

It was just touching the door of the main-controlling room, and about to enter there.