"Haaah, that's great..." Rei was bathing in cold water with his eyes closed.
There were many bathrooms in the mansion, all were big, but the one he is currently in was almost the size of Olympic pool.
Bath itself was of pure white in color, and the room itself was enormous.
It was a personal space were only the most trusted people in the family have access to.
Sunlight illuminated the room warmly, gently.
The birds song a beautiful melody, bringing joy to Rei's ears.
The cold water took away the heat from his body, making him relaxed.
As early in the morning as it was, Rei was taking a bath after a training session.
He can only do a few push-ups, sit-ups and squats before his muscles are exhausted, but it was better than nothing.
He was also not alone.
'Fuck, fuck, fuck, fuck.' His mind was a mess.
His mother was siting naked, right beside him, in all her glory.
'Why the fuck are you so perfect?!'
Her boobs were gorgeous, full, with perfect form.
Pink nipples adored the tops, almost making him drool.
They jiggled with slightest movement, which was extremely mesmerizing.
Her ass was no less perfect.
Bouncy, big and juicy.
Rei wanted to use them as pillows due to how damn soft they looked.
But of course the main focus of his was her absolutely stunning, perfectly shaped, pink pussy.
There was not a trace of hair there, so he had full picture wherever he sees his mother standing.
Fuck, what he wanted to do with it. He feared this chapter might become R-18 just from his thoughts.
Every single part of her was perfect.
It was often difficult for him to control his emotions, his hormones were very unstable.
Not to talk about naked Rose, the most beautiful woman Rei ever saw,
even maids, in their tight dresses, with their divine appearances, were driving him crazy.
Last 3 month were like a torture to his emotions.
Like the most delicious dishes were laid in front of him, and he can only look.
He was scared for his teenage years, where his hormones will explode.
'Patience, Rei. Patience. One day I will take everything I want.'
He started to take deep breathes to calm down, something he already become used to doing.
Rose stared at him predatory, and in the very next moment, Rei was already right beside her face.
"Kyaaaa, you are soooo cuuuute." She started to rub his cheek with hers, while giggling.
'How do we always end up like this? Well, it's not like I'm against it.'
He was not even startled at this point. Just enjoying her swaying breasts.
"Mooom, I'm dirty..." He protested.
"It's your fault for being so cute."
'...She is so childish, MY mother...' Gurl. 'Ugh.'
"Oh, you are hungry already? Here we go..."
She brought him closer to her tit and basically forced him to drink.
Rei never refused his mother's milk, it was full of nutrition and helped his body grow.
He needs twice as much food as other children his age. After all, training does take a lot of energy from him.
-------------------
With time, Rei learned not to fall asleep after food.
Which was pretty difficult, like going against an instinct.
Rose decided to leave first, and called Saya to take care of him instead.
After all, Rei was not her only child who needs care and attention.
"Young master." She bowed slightly.
"Oh, my favorite vampire is here." He smiled teasingly.
Her face immediately became red like tomato.
She was extra sensitive to his remarks.
'How cute, why didn't I tease girls back on Earth?'
"Come on, just scratch my back a bit, my dear maid."
"Y-yes, master Rei."
-------------------
"4 + 5?"
"9!"
"That's right. 11 + 3?"
"14!"
Mei was a very fast learner, not only did she already knew numbers up to 20, she also learned basic math with Rei's help.
For a 2 years old child, it was a big achievement!
"You are great at it!" He patted his sister's head.
And she was extremely happy about that, she was literally shaking with happiness!
He could almost hear her pour, like a kitten.
His patting didn't look comical. Their height difference was not as big as one might expect.
After a lot of training and hanging on trees, Rei's height already approached that of a 1 year old boy, being just under 74 centimeters.
Mei, on the other hand was on the lower side for her age, about 85 centimeters.
'It's been 5 month since my rebirth. And I'm yet to have any issue in life.'
"What about 3 * 4, Mei?"
"It's... Uhm..." She started counting on her fingers, and after a few seconds, "12!"
"Haha, right. You are very smart, Mei." He said calmly.
It was a very peaceful time for him, just teaching his sister math.
Rei was always a bit of a nerd, learning everything he can, and very fast at that.
What took others months, he can do in a few hours of practicing.
So it was very satisfying to teach another smart person.
"Let's stop for today, shall we?" Rei asked with a smile.
'Humans need rest to learn, there is no need to tell her everything at once.'
"H-huh? N-no! Let's study more!" She sounded almost desperate.
For her, Rei was the best brother ever.
The person she spent the most of her time with.
The person she is most familiar with.
The person she looks up to, despite being the older sibling.
He always plays with her, teaches her and, overall, cares about her.
It wasn't even Rei's intention, he was just being himself.
'She's like this again.'
"...Want to play hide and seek?"
The smile bloomed on her face, beautiful, real, without any hidden intensions.
"YES!"
'She's so exited. Cute. Ah, my heart...' Cuteness was his weakness.
-------------------
Rei moved his hand to the left dramatically.
With such a serious face, one would expect something big to happen, but nothing, not even a wind.
Things were different for Rei thought, he saw the discrepancy in light, the slight bend in place where he changed mana flow.
Of course, the effect was too small for his eye to perceive.
Instead he used a system of lasers that multiply even the slightest change anywhere in the laser's path, to a degree, where he can see it with a few magnifying glasses.
And a hand movement? He just found it easier to concentrate.
That alone gave him a lot of information.
Only place where he change the mana flow has been bend.
The form of the bent is also important.
It was a form of a probability distribution function (PDF).
"So mana can affect space itself, and that effect is somehow tied to probabilities.
How interesting."
Is was not something unfamiliar to him, the whole quantum physics field was build on top of probabilities.
'Right now I can only affect parts of natural mana flow by less then a micrometer.
Which is not particularly useful.
I also need a better measurement for this.'
What he perceive as a change in natural mana flow, was like changing the course of a river.
One can do it by just a few millimeters, or by the whole kilometers.
But that measurement is very vague, and not particularly intuitive.
Especially considering that mana flow is tree-dimensional, and at all places simultaneously.
'I should create a mana framework independent to the one of this world.'
Currently Rei can sense mana's density, flow vector, speed, and something else he can't quite describe.
'But my current knowledge is still lacking to create any coherent system.'
It was pretty difficult to create something completely new.
Especially something akin physics framework, nature of which is complex by itself.
"I'll start with basics."
As an experienced programmer, it was much easier for him to create a new project.
So, he immediately started writing and drawing the draft.
'''
Mana Dynamics Theory V1.
Flow vector (V3) - Average direction of mana movement in a given area. Measured in a 3D vector (x, y, z).
Density (D) - Mana density in a given area. Measured in Si.
Speed (S) - Speed with which mana moves in a given area. Measured in Si.
Force (F) - Force applied to change mana flow in certain area. Measured in flux.
Currently calculated by the volume of change in mana flow and `D`.
'''
"This will give me some starting point." He smiled proudly.
Of course, he may be wrong in many of his observations, he probably will, in fact.
But that what science is, making errors, learning on them and evolving.