It's Just a Business Relationship
"Squeak, squeak...."
Serena, the utterly ruthless mastermind who had embezzled no fewer than four mice from the great Sirius Duke House, headed straight for her guest room on the third floor.
"Ehehe... baby smell... Ah. Young miss, you're back."
Serena stared blankly at her personal maid, Serasia.
Come to think of it, she really was a suspicious one.
Barging into her bed without permission... well, that was suspicious enough on its own, but every single thing the girl did was suspicious.
It had already been seven years since Serasia became her personal maid, and in all that time her appearance had not changed in the slightest.
She told me she was seventeen when we first met, and even now she shamelessly insists she's still seventeen.
The problem was that she had to be at least in her mid-twenties, yet she genuinely looked seventeen.
Is this girl even human?
If that had been the only oddity, Serena might have simply chalked it up to excellent skincare. But if you watched her closely, her stride was unnaturally even, as though she had undergone professional training, and her footsteps were suspiciously silent. She also used her strength in ways that defied common sense... which was why Serena suspected her of being a secret weapon the family was raising in secret.
It was one of the main reasons Serena regarded the Meridiana Count House as the empire's shadowy masterminds.
They probably assigned her to me as both bodyguard and watcher.
Anyway.
Right now Serena needed this suspicious maid's knowledge.
She trudged over and sat down beside Serasia.
"Hey, Serasia. Can I ask you just one thing?"
"Yeees."
"How much arsenic does it take to kill a person?"
The question was delivered in the same casual tone one might use to ask what was for lunch. Serasia felt no particular sense of wrongness and simply answered with what she knew.
"For an adult man, a generous 150 milligrams will do the job."
"Is that so? Thanks for telling me."
So she really does know. What a suspicious girl.
But she was being helpful at the moment, so Serena gave her head a few fond pats before rising to her feet.
Serasia rested a hand over the spot her mistress had touched and smiled bashfully... then her eyes went round.
"Huh?"
"What did I just tell the young miss...?"
Serena snorted inwardly.
What did you tell me? You just casually shared your personal experience poisoning people, you secret weapon of a mastermind family.
Feeling the darkness of her house all over again, Serena left the ducal residence with her embezzled mice in tow.
At the pharmacy she purchased rat poison made from arsenic. According to the ingredients list, a rat would die from only one-thirtieth the dose that would kill a human.
She also bought nutritional supplements and headache medicine, then rented a room at an inn some distance from the ducal residence.
Here she planned to run an experiment: feed each mouse a different mixture of rat poison, Lumina's medicine, the supplements, and the headache pills.
Doing something like this inside the ducal residence would look far too suspicious, so she had deliberately secured a separate location.
Once inside the room, Serena transferred the mice into the cages she had brought along and stared at the bottle containing Lumina's medicine.
Vireyer had said Lumina would die within a year at the shortest, two years at the longest. She had also instructed that Lumina take one of these pills every day, which meant Lumina would swallow a total of 730 pills over two years.
Put another way...
Lumina will take a total of 730 of these pills until the day she dies.
Twist that statement a little further and set up a hypothesis:
Lumina dies after taking 730 of these pills.
An adult man needs twice the dose of a child, so for an adult that would be 1,460 pills. A rat's toxin tolerance is one-thirtieth of a human's, therefore...
If Lumina's medicine is poison, a rat will die after roughly fifty pills.
Of course, even ordinary medicine becomes dangerous if you swallow two years' worth at once. That was why she had prepared the supplements and headache pills as well—so she could compare the side effects of massive overdoses.
Serena mixed each of the four mice a portion of feed laced with, respectively, rat poison, fifty days' worth of Lumina's medicine, fifty days' worth of supplements, and fifty days' worth of headache pills.
Three days passed.
The mouse that ate the rat poison died within a day. The one that ate Lumina's medicine died after a day and a half.
The mouse given the supplements threw up violently at first, then recovered almost immediately and was cheerfully squeaking about again. The one given the headache medicine was clearly suffering, but not enough to die.
Lumina's medicine was unmistakably suspicious.
Serena carefully examined the mouse that had died after eating Lumina's pills. Just like the one killed by rat poison, it gave off a faint garlic odor.
Garlic smell was a classic symptom of arsenic poisoning—something she had read in the rat poison's instruction leaflet.
Lumina's medicine contained arsenic.
Lumina... you weren't terminally ill because you were sick, were you?
She wasn't dying of illness. She was terminally ill because she was being poisoned.
That duchess... the moment her own son is born, she starts trying to eliminate her stepdaughter.
If Lumina were poisoned right after the birth of a legitimate son, suspicion would fall too easily. So she had carefully adjusted the arsenic concentration to make the girl waste away over two full years.
Having a maid administer the doses instead of doing it herself was simply so the duchess wouldn't have to dirty her own hands. And if the plot ever came to light, she could always pin the crime on the maid rather than herself.
That was why Serena had been made Lumina's maid in the first place.
She finally gets a maid of her own, and it turns out to be the person meant to kill her... how tragic. Truly tragic.
Serena carefully tucked the medicine Vireyer had given her into her clothes. She would need to keep it safe; one day it might serve as evidence.
What if Vireyer asks whether Lumina is taking her medicine properly?
She could just buy some similarly shaped supplements and feed those instead. That should fool her well enough.
As soon as she finished cleaning up after the experiment, Serena went looking for Lumina.
The fourth floor—space used for storage and servants' quarters, cold when it was cold and hot when it was hot, thoroughly unpleasant. And even there, the most sunless corner room of all.
Lumina was sitting on the edge of the bed again today, blinking unfocused eyes at empty air.
"Hello."
"..."
Lumina tilted her head slightly at Serena's greeting, but that was all. She showed no further human reaction.
Serena sat a short distance away.
For all that Serena had declared they should become friends at their first meeting, the distance between them over the past three days had always felt like this.
Lumina, for her part, did not want to create any lingering attachments when she was already dying. Serena, for hers, did not want to grow fond of a child who would soon be dead.
For those reasons the two of them shared the same space yet never exchanged anything resembling genuine human contact.
But today Serena had realized that Lumina was not terminally ill at all.
Then there's no reason to keep my distance, is there...?
She shook her head at the thought.
Whether Lumina departed for heaven or Serena became a maid of the Altair Duke House, they would still part ways in two years. There was still no real reason to get attached.
It's just a business relationship.
That was Serena's conclusion.
That was Serena's conclusion, and yet...
"...Lady Lumina."
"...What."
"...The air is cold."
"...It is."
"...May I hold you?"
"...Do as you like."
By the time she came back to herself, she was holding Lumina tightly in her arms.
It wasn't because she particularly liked Lumina.
It was just... the child was pitiful, wasn't she?
And if that was the case, then even without liking her, she could at least feel a little sympathy, right?
Ahaha. How did things end up like this...
At first she had only planned to fail the interview and go home. Now here she was, feeling sympathy of all things.
You really never could tell what life would throw at you.
"..."
Perhaps she hadn't minded being held after all. Lumina soon began breathing in soft little snuffles and fell asleep against Serena's shoulder.
Serena cast the Meridiana Count House's secret magic, Weakness Camouflage, upon the sleeping girl.
The spell Serena privately called her "fake-illness magic" had the power to make its target appear frail and sickly regardless of their actual health.
I was told the family invented it back before they became a conglomerate, so they could drive down the price when buying livestock...
That was what she had been taught, but of course it was a lie. Its real purpose was to cast it on people and let them play at being ill.
Dig a trap in advance, deliberately show a weakened appearance to hostile forces and lure them into it. Drag out a lawsuit by claiming illness. Or, when accepting an assassination contract, reverse the deal with the target and stage their death instead.
What I'm about to do is the same sort of thing...
Serena planned to gradually strengthen the Weakness Camouflage on Lumina over the course of two years until she could fake the girl's death completely. Once they had held a funeral and thoroughly convinced the Sirius Duke House that she was gone, she could spirit Lumina away to a villa of her own.
If I can become a maid of the Altair Duke House, I can at least do that much for her.
They said that to deceive your enemies, you first had to deceive your allies. Because ten-year-old Lumina might still make mistakes, Serena decided not to tell her the truth.
It'll be hard, but hang in there just a little longer.
Now that she was under Weakness Camouflage, Lumina would believe she was truly dying and put on a thoroughly convincing performance as a terminally ill girl.