Mashu quickened her pace, holding the clipboard more securely.
"Senpai, Da Vinci-chan said today is just a light test. Nothing dangerous."
Kazuya snorted.
"She always says that. In the end, I wake up with some new device monitoring even the number of my blinks."
"It's cutting-edge technology." Mashu tried to defend, but her smile betrayed that even she didn't fully believe it. "It's… useful. Sometimes."
"Useful for whom?" Kazuya asked. "Definitely not for me."
Merlin flashed a wide smile.
"At least if something explodes, it's always fun. The last time the lab caught fire, Nikola Tesla came running with an extinguisher as big as he is."
"You're not supposed to laugh, Merlin-san…" Mashu murmured, but she had to look away to hide her laughter.
The laboratory door appeared at the end of the huge corridor, reinforced with three layers of locks.
The kind of door that clearly said: irresponsible things happen here.
Mashu raised her hand to touch the panel.
"I'll open it."
Kazuya raised an eyebrow.
"Mashu, you always get nervous when entering this lab."
She hesitated for a second… and silently confirmed with a shy nod.
Merlin gave the girl a gentle pat on the shoulder.
"Courage. If anything goes wrong, I'll protect you."
Kazuya crossed his arms.
"You? Protect? What are you going to do? Throw explosive flowers?"
Merlin smiled, beautiful and completely shameless.
"Exactly."
Mashu took a deep breath and touched the panel.
The scanner glowed, analyzing all three at once.
BEEP — Access granted.
The doors opened with a soft hiss.
And the first thing that appeared wasn't Da Vinci.
It was smoke rising slowly from the left corner of the lab.
The second thing… was Tesla's voice.
"I told you NOT to connect the cables inverted, Da Vinci!"
"And I said I was in control!" Da Vinci replied, offended. "A little smoke means progress!"
Well, anyone unfamiliar with their world would certainly be shocked to discover that the famous Leonardo da Vinci was, in fact, a "woman" when summoned as a Servant.
Though historically a man, Da Vinci never insisted on maintaining that form. He claimed, with all the conviction of the genius he was, that the Mona Lisa represented the absolute ideal of beauty he had sought throughout his life. Therefore, he saw nothing wrong with assuming her appearance. Yes… he decided to become her.
A woman 1.60m tall with one of the most perfectly proportioned bodies. With soft curves in her breasts, buttocks, and thighs, everything harmonized to form a stunning image. Her face was a perfect balance between beauty, a maternal air, and seduction. It almost seemed as if, when measuring her features, they would all have the "ideal" size and shape, making other beauties seem pale imitations, with the only exception perhaps being goddesses. Her dark brown hair, shiny with a slight burgundy tone, fell in soft curls around her neck and shoulders, appearing at the peak of health due to its natural glow. Her eyes were like a masterpiece, meticulously painted by the world's most skilled artist with all his passion. Though they had a base color resplendent like sapphires, there was a mixture of subtle greens, purples, and a minimal touch of pink that seemed to swirl in her intensely intelligent eyes.
Her clothes evoked a bit of the noble European style of the 16th century, with very striking colors like red and blue, featuring various folds and other details in gold. The main outfit consisted of a dress, made up of a short pleated red skirt, long stockings, and fabrics that completely covered her back...
"It means burning equipment again!" Nikola Tesla was quite upset as he retorted.
He was a man of imposing and aristocratic presence, with a serious and almost indifferent countenance. His face was long and defined, marked by rigid features that gave him a natural expression of authority. His eyes, cold and evaluative, seemed to observe everything around him with calculated calm, while his slightly arched eyebrows reinforced his aura of severity. His dark, straight hair, neatly combed back, reached his shoulders, but what drew the most attention were the tips dyed in a vibrant turquoise blue, which broke the rigidity of his look and added a touch of elegant strangeness.
He wore extremely sophisticated, almost ceremonial clothes. The high white collar, voluminous and ornamented, evoked Renaissance attire, matching the equally white and wide cuffs that protruded from the sleeves. The dark purple tunic, impeccably fitted to his body, featured double rows of silver buttons reminiscent of high-ranking military uniforms or those of an aristocratic officer. Behind him, a long black coat opened like a dramatic cape, flowing at the sides and reinforcing his haughty and elegant posture. The pants, also purple and tight, further elongated his legs and created a refined silhouette, finished with perfectly polished white shoes.
The most striking detail was his right hand: a robust and articulated golden metallic prosthesis, which he extended forward in a firm gesture. The piece had a mechanical and functional appearance, suggesting high technology, magic, or perhaps a past battle that forced him to replace his original hand.
Hearing the two arguing, Kazuya sighed...
"Great. It's Tuesday, then."
Merlin waved as if greeting quarreling neighbors.
"Good morning to you too."
Da Vinci spun around in the chair she was sitting in.
"Kazuyaaa! You're here!" She pointed at him as if announcing a prize. "And you brought Mashu-chan and Merlin too! Excellent. The main volunteer and the two support volunteers."
"I didn't agree to be a volunteer." Kazuya said.
"You never do." Da Vinci replied. "That's why it works."
Tesla looked at the newcomers.
"Finally, some sensible people arrived." He looked at Kazuya. "Make her stop before the entire lab's wiring collapses..."
"Not again…" Mashu murmured, pale.
Kazuya shrugged, completely calm.
"What are you building this time?"
Da Vinci slapped the side of the machine that was still emitting smoke.
"The Sentiment Scan Deluxe 3.0! An improved version of the old emotional sensor."
Kazuya blinked.
"But the old one already worked."
"Of course it worked!" Da Vinci spread her arms. "It worked poorly!"
"It worked… normally." Mashu tried to argue.
Tesla raised a finger.
"It worked with 48.6% efficiency. Shameful."
Kazuya tilted his head.
"So what do you want a detector to do? Read emotions like anime subtitles?"
Da Vinci clapped her hands.
"That would be amazing! But for now, we just want it to identify aura fluctuations and mental state."
Kazuya narrowed his eyes.
"Mental state… why?"
Da Vinci smiled in that way that never boded well and looked away: "Because you're surrounded by wives in emotional Berserker mode. I need to monitor before one of them breaks you."
"..."
Kazuya sighed.
"Fair."
Merlin raised her hand.
"I want one of those detectors just for me. That way I can see when Morgan is about to throw a spear at someone."
Da Vinci blinked.
"You want one? I can make a portable version."
Tesla slammed the counter.
"You can't! It will destabilize the invention's structure!"
Kazuya looked at Merlin.
"Even if you use it on Morgan, you'd still be the target.... Artoria Lancer would throw the spear at you anyway."
"Exactly!" Merlin agreed. "That's why it would be useful!"
Mashu took a deep breath, trying to stay focused.
"D-Da Vinci-chan… what's today's procedure?"
Da Vinci made a dramatic gesture.
"Very simple! Kazuya enters the cabin, we keep an eye on the readings, make adjustments, avoid explosions, and—"
Tesla interrupted.
"And try not to recreate last week's accidental electrical storm."
"It was an artistic side effect." Da Vinci said.
"It was dangerous!"
"It was beautiful!"
Kazuya sighed for the third time in five minutes.
"Okay. What do I do?"
Da Vinci pointed to the cabin in the center of the lab, a reinforced glass capsule full of blue lights.
"Get in there and relax. Don't touch anything. Don't kick anything. Don't threaten anything. Just stand still."
"I always stand still." Kazuya said.
Merlin coughed, clearly lying with the sound.
"Yes, sure. Still."
"Kazuya-senpai really doesn't stay still." Mashu raised her hand.
"He really doesn't." Tesla confirmed.
"You three should stop talking." Kazuya murmured as he walked to the cabin.
Merlin followed behind him as if going to watch a show.
Mashu also approached, but with technical attention, ready to note everything.
Da Vinci adjusted levers, turned knobs, and connected cables.
"All set! Tesla, you handle the energy flow! Mashu, monitor the secondary panel! Merlin… don't touch anything."
"Did I disappoint you?" Merlin asked.
"Profoundly."
Kazuya entered the cabin, resting a hand on the glass wall.
"Okay, Da Vinci. Start already."
Da Vinci smiled.
"At your command, my favorite male model."
Tesla murmured behind:
"This is scientific favoritism."
"Absolutely." Da Vinci responded proudly.
She pulled the main lever.
The cabin lit up.
Lights flashed.
Tesla crossed his arms.
Mashu watched the monitor with sparkling eyes.
Merlin leaned against the glass, curious.
Kazuya remained still, bored expression.
And Da Vinci smiled, satisfied.
"Perfect. Now… let's see how long until this goes wrong."
The cabin continued emitting a soft hum, blue lights running along the edges as if breathing.
Mashu followed every oscillation on the panel, Tesla adjusted a metallic dial, and Merlin… pressed her face against the glass like a child looking at an exotic animal.
Da Vinci leaned over the main console.
"Okay, Sentiment Scan Deluxe 3.0… show the world the result of my genius."
A short beep sounded.
Then another.
And then… the central screen flickered, projecting lines, graphs, and a set of colorful readings.
Mashu widened her eyes.
"Oh! It's working!"
Tesla also approached, clearly interested.
"Finally. A stable reading."
Merlin tapped the tip of her finger on the glass.
"What's the Master's mental state? Curious."
Da Vinci didn't answer immediately.
Her eyes followed the screen for long seconds.
Then a few more.
And then… she frowned.
Deeply.
It wasn't a normal frown; it was the kind Da Vinci only made when she was about to throw an entire machine in the trash or when she discovered something too important to be said without caution.
Mashu leaned in, worried.
"Da Vinci-chan? What is it?"
Da Vinci didn't answer.
Her fingers slowly slid over the controls. She saved a copy of the graph, pressed two extra buttons that shouldn't be part of the basic test, and zoomed in on the reading.
Tesla drew closer.
"What's going on? What are the indicators?"
Da Vinci abruptly closed the screen.
"Everything normal."
Mashu blinked.
"Normal…? But you—"
Da Vinci quickly raised her finger.
"Laziness."
"...huh?" Kazuya grumbled inside, without even opening his eyes.
"That's it." Da Vinci waved firmly. "He's in a lazy mental state. Sleepy. Relaxed. Basically, standard Kazuya mode..."
Tesla frowned.
"Are you sure? If it were laziness, the mental activity peaks should—"
"It's laziness!" Da Vinci insisted, smiling too widely. "Complete. Absolute. His mental health is also perfect. Perfect indeed!"
Mashu tilted her head, suspicious.
"Are you really sure?"
"Of course! I would never lie in a scientific test." Da Vinci declared with a hand on her chest.
Tesla crossed his arms.
"You lie in all of them."
"And I do it with elegance!" Da Vinci retorted.
Merlin narrowed her eyes, looking back and forth between Da Vinci and Kazuya.
"Hmmm… you're hiding something."
"I'm not." Da Vinci responded too quickly.
"Then tell me what his emotional graph is." Merlin asked, very casually.
Da Vinci kept her smile frozen.
"Flat line."
"Flat line?" Mashu repeated.
"Yes! Classic behavior of someone very, very… relaxed. Nothing more!"
Tesla frowned even more.
"Why would the line be oscillating as if trying to form patterns?"
Da Vinci pressed a random button.
The screen went off.
"Monitor bug!"
"A monitor bug never does that." Tesla complained.
Da Vinci raised both hands.
"Everything is within expectations! Absolutely correct! You can trust it!"
Merlin rested her chin on her hand.
"Da Vinci…"
"Hm?"
"If I open this cabin, do the readings change?"
"No!"
"Even if I hug him?"
"Definitely don't hug him!"
Kazuya opened one eye inside the cabin.
"What are you all doing out there?"
"Nothing, Master!" Merlin replied with the most suspicious smile in all of Chaldea.
Da Vinci cleared her throat, trying to control her own expression.
"Anyway! Test complete! He's fine! Zero emotional problems! Absolutely nothing unusual!"
Mashu kept looking at her, still suspicious.
Tesla too.
Merlin smiled, clearly perceiving something was hidden, but didn't press.
Da Vinci spun her chair away from the group and pressed her lips together. She had never seen someone with such precarious mental health; that traumatic past had marked him more than anyone could suppose. Deep down, she knew she had done the right thing in building that machine; curiosity had guided her, as always, especially when it involved her master, practically omnipotent like her.
Though the justification for the invention sounded, at first glance, like a mere whim, after witnessing everything her master had endured in the dream cycles, she felt it was her duty to act. She was grateful for bringing her to that new world; this was her way of repaying.
Since arriving, her curiosity had only grown. Da Vinci analyzed every artifact and every phenomenon, dismantling concepts until reaching their foundations, then recomposing everything into something new. It was almost a ritual: understand, deconstruct, create, always pushing the idea to its limit. The last time, driven by this impulse, she built a flying machine inspired by a bird's wing beats. But upon contemplating the Red Dragon and its enormous wings capable of sustaining a colossal creature, another question sprouted in her heart: how could something so gigantic fly? And also, the Sacred Gears of this world, which were artifacts of God—how had the Biblical God created them? Everything left her full of curiosity in this world, and she spent most of her time studying...
How could she not be grateful for this gift?
She took a deep breath, spun her chair back, and smiled brightly.
"Congratulations, Kazuya! You are officially healthy, lazy, and totally normal!"
Kazuya gave a lazy wave.
"Ah, great. Then let me out of here before I fall asleep standing."
"You can come out!"
Da Vinci opened the cabin.
As Kazuya stretched, Merlin observed him with a curious look.
Mashu still seemed a bit lost.
Tesla murmured:
"A completely unknown mental reading, but she says it's laziness. And I'm the irresponsible one."
Da Vinci didn't respond.
She just smiled.
A smile that said:
I can't tell this to anyone.
__________________
(A/N: Did you enjoy the chapter? Then you should know that over on my Patreon you can read up chapters ahead for just 5USD! And yes—for that price, you also get full access to all of my content. That's right: cheaper than a snack… and with way more drama, action, and guaranteed emotional damage.
The link is right below. See you there!
My Patreon: patreon.com/Adam_Kadmon
Thank you so much for your support — you make all of this worthwhile.)