The Hero Became The Son of The Demon Queen

"Hum hum hum~."

The dark mage, Vilma, hummed a tune as she immersed herself in her research.
"Ah, it's so good to be researching alone!"
During the war with the Demon Lord's army, dark mages were divided into those who protected the continent and those who followed the demons. This remained the same even after the war ended. The dark mages who had joined the Demon Lord's army were driven to the Demon Realm where the demons lived.
In other words, all the dark mages remaining on the continent were those who had fought alongside the continent. However, the name "dark mage" was prone to prejudice. This was partly due to the fact that the dark mages on the demon side during the war had been so cruel and terrifying, but also because the magic they dealt with was often gloomy and eerie.
Because of this, dark mages had to endure prejudiced gazes and a kind of persecution.
It was the same for Vilma.
Unable to bear those gazes, Vilma ran away from home. Of course, that wasn't the only reason, but the biggest reason was the gazes of others.
She escaped from the magic tower and fled to another country, finding her own hideout.
She had also experienced near-death situations, but fortunately, she was able to settle in an ownerless dungeon.
That was just 10 days ago.
Today, Vilma was also happily engrossed in her research.
Especially today was a very good day.
Ideas suddenly flowed, and she made progress in her research that had been stalled. She was able to concentrate well, and for some reason, the mana in the dungeon was also denser than usual. Moreover, she had even discovered a rare herb when she went out to collect reagents at dawn.
It was as if the heavens were blessing her for living in this dungeon.
Until someone appeared with a flash of light.
"…Huh?"
"…Oh?"
"..."
Vilma, who had turned her head at the sudden surge of mana from behind, froze.
Two beings appeared with the light. One had dark red hair, but the other had purple hair. It was common knowledge to everyone on the continent that purple hair was a symbol of succubi.
"Eek!! Wh, who are you!!"
Vilma pointed at the two people in fright.
"Hmm, I didn't expect someone to have settled here."
"This is an unexpected situation."
"Well, it seems like a dark mage, so we can just make them one of our subordinates."
"That's a good idea."
The two of them talked amongst themselves, ignoring Vilma who was yelling.
It was a rambling conversation, but Vilma was a dark mage who was considered a genius in her place.
She wasn't a fool who wouldn't understand the situation after hearing this conversation.
"Wa, wait… De, Demon Lord's army?!"
"Haha, that's right."
The boy calmly smiled and affirmed.
Vilma intuitively realized that this boy held a higher position than the succubus.
He had black hair mixed with his hair, a symbol of a demon hybrid, and unlike the succubus who was clearly an adult, he looked like a boy to anyone.
But there were many clues.
The succubus who spoke to the boy with respect. The way he took the initiative in the conversation even though the succubus was silent.
And most importantly, the surrounding mana was fluctuating around him. It was proof that the central caster of the spatial magic just now was the boy in front of her.
She didn't know where they had come from, but if they had come directly from the Demon Realm, it meant he was at least a master-class mage.
"Keuk!"
Compared to him, she was still an expert-class. Even one rank was a difference that couldn't be ignored.
Unlike her hometown, there was no one here to help her. The only thing she could rely on was her own magic.
She quickly reached out for the magic wand she had placed nearby out of habit. The saying "the early bird gets the worm" also applied to mages. Even if she couldn't win, it was enough to buy time to escape.
However, for some reason, her body wouldn't move. It felt like her whole body was being constricted.
"?!"
She slowly turned her head and looked at her body.
As expected.
Something black, shaped like a wide line like a bandage, was constricting her body.
'Dark magic? Shadow? No, this feeling, this smell is…'
"…Ink?"
"Oh, you seem smarter than I thought?"
"She's not as good as you, but she seems quite useful."
Before she knew it, the ink crept up and covered her eyes.

The difficulty of acquiring fluid magic, which controlled gas and liquid, was C-rank. To handle ink so freely like this, it might even be a derivative magic created by modifying magic. This was also something only a master-class could do.
'Ha…'
All the energy drained from her body.
'No wonder I was having such good luck today…'
It seemed like all the events of today were foreshadowing what was happening now.
"Most of the things are still here, so it seems like you haven't touched much. Or maybe you haven't been here long."
"But did you notice?"
"Of course. This is quite interesting, isn't it?"
The two of them talked without caring about her even though she was bound.
Their voices exuded overwhelming confidence. Only then did Vilma realize the identity of the anxiety that had been growing in her chest.
An overwhelming sense of defeat.
There was nothing she could do to defeat those demons with her current abilities.
The ink wriggled up and began to cover her mouth and ears. Even though they were so strong, they were going to completely eliminate any chance of her playing tricks. She got goosebumps at their meticulousness.
Before her mouth was completely blocked, she blurted out her inner thoughts without realizing it.
"Su, surrender… I'll do anything, so please spare me…"
"Really? I like how quickly you assess the situation."
The boy's voice echoed in her ears, and then silence fell.
"Name, Vilma. Age, 25. Gender, female. Belonged to the Imperial Magic Tower of the Dejak Empire, but ran away from home recently and settled here."
"Th, rather than running away, it was more like leaving home for free research…"
"Huh? What did you say?"
"No, I mean I ran away…"
Vilma immediately lowered her tail and bowed her head.
The boy sat on a chair and looked at her with an interested gaze.
Currently, Vilma was kneeling on the floor, freed from the ink's restraints. But she had no intention of resisting them. Let alone resisting, she didn't even have the will to run away.
While she was restrained, the boy and the succubus had found everything Vilma had set up in the hideout.
On top of that, Irena had even placed a restriction on her. In effect, Vilma was now no different from an ordinary human.
"Hmm. Your specialty seems to be dark magic."
He turned his head slightly and looked at the books Vilma had been reading until just now. There were a few of other types scattered here and there, but most of them were related to dark magic.
"Ca, can you see that just like that…?"
Vilma's eyes widened.
Even if they were master-class, they were often ignorant of magic outside of their own field.
In the first place, there were hundreds of types of magic in this world besides the nine major types. Moreover, if you included derivative magic and unique magic, there were many similar types of magic. Lastly, dark magic was a minor magic that few people used.
"Roughly."
Vilma's gaze towards him changed. There was still a hint of fear in her eyes, but now there was a slight hint of respect.
"Well, let's get down to business. As you may have guessed, we're demons. We were going to use this place as a hideout to infiltrate the continent, but you happened to be here? I thought about killing you, but you seem to have some talent, so it's a shame."
"…Hehehe, I do have some talent."
Vilma was strangely shy and happy at the simple compliment. It seemed like she wasn't used to being praised.
His eyes sparkled with interest. At first glance, Vilma's level was high for her age. Yet, the fact that she was awkward with compliments meant one of two things.
Either her teacher was very stingy with praise, or there was an even greater genius around her.
'The latter.'
The Imperial Magic Tower was the best magic institution on the continent. Even if it wasn't her teacher, there would have been many mages who would have praised her.
Then it was more likely that Vilma had been overshadowed by the presence of an even more talented mage.
"Interesting."
"Yes?"
"No, it's nothing. So, what do you think? About becoming my subordinate. You'll be my glorious first human subordinate."
"Uh…"
Cold sweat ran down Vilma's back.
She had said she would do anything to survive and surrendered, but when she heard him say to become his subordinate, her hands and feet trembled.
What if she became a subordinate of a demon and got caught?
She wouldn't just be driven to the Demon Realm, but would be killed if caught. A disciple of one of the elders of the Imperial Magic Tower becoming a subordinate of a demon? It was only a matter of time before the magic tower fell apart, and the prejudice against dark mages would undoubtedly become even stronger. And if her identity was revealed…
"I, I, th, that…"
He somehow found it funny to see Vilma trembling and unable to speak properly. For a 25-year-old woman, her behavior was too cute.
"Dark magic… not much progress, right?"
"…Yes?"
"It can't be helped. There aren't many dark mages who properly delve into dark magic. And many dark mages died during the war."
"..."
"But you know what? Dark magic is more developed on the demon side than on the continent?"
It might have been a trivial statement, but it was enough to shake Vilma's heart.
It had only been 18 years since the war ended.
Both sides were exhausted, but the demons were even more so.
The demons weren't going to start another war anyway, so what was the harm in becoming a subordinate of a demon? She remembered the saying she had heard somewhere that if you don't get caught, it's not a crime. That was right.
As long as she didn't get caught, wouldn't it be okay?
"I, I'll… become your subordinate…"
"Good thinking."
He smiled gently at Vilma's answer and then made a look as if he had just remembered something.
"Ah, come to think of it, there's a magic I want to experiment with."
"…Yes?"
"Actually, this magic is the key to infiltrating the continent. It's one of the three most important factors."
"Ex, excuse me? Lord Demon?"
"I mixed tattoo magic, contract magic, and charm magic as a base and added some other things, but I haven't been able to try it on a person yet."
He firmly continued what he wanted to say, ignoring Vilma who was flustered and trying to say something.
"The main purpose is obedience and restriction, but since everyone around me is overflowing with loyalty… I couldn't tell if it was really effective. Well, there are many other effects too."
"De, Lord Demon? I can be completely loyal with just the contract magic!"
"But I just happened to find a good subject. Don't worry too much though. I don't really need to verify it, but I just thought it would be nice if you were the first subject."
The boy smiled brightly and stared at her intently.
Vilma trembled.
She didn't know what kind of magic it was, but the base magic itself was ominous. But no matter how she thought about it, the demon wasn't asking for her opinion, but rather giving her a one-sided notification. And she didn't have the courage to refuse that notification.
"I, I'll receive it…"
"Really? That's a relief. Then first… hmm."
He stopped talking and hummed, scanning her up and down.
"Why are you doing that…?"
"Oh, nothing… it doesn't really matter. Then first…"
Gulp.
What was he going to do to her? She swallowed her saliva and waited for the next words.
"Can you lift your skirt?"
"…Yes?"
"Lift your skirt. Skirt. I need to see your stomach. But your clothes are a one-piece dress, right? To see your stomach, you have to lift the whole skirt."
"Uh, uh…"
Vilma's pupils shook violently. It was an even greater reaction than when he had asked her to become his subordinate.
"What are you doing? We don't have time. Or should I lift it?"
Mana was gathering in the boy's right hand.
"Sniff… Ye, yes…"
With tears welling up in her eyes, she sniffled and slowly stood up.
Her eyes were wet with the thought that he might kill her if she made a mistake. Of course, it was a misunderstanding, but it wasn't unreasonable for her to think that way.
She brought both hands to her knees and grabbed the hem of her skirt.
She hadn't expected that the one-piece dress she had worn because the dungeon was warm and she didn't want to bother with separates would lead to such a disaster.
She slowly lifted her trembling hands.
"Haa…"
Even though the dungeon was filled with warm air heated by magic, her thighs felt cold every time she lifted her skirt. She could feel the gaze of the boy sitting in front of her on her slender thighs.
The boy wasn't smiling, nor did he have a sexual look in his eyes. But for some reason, her lower abdomen itched.
"Ugghh…"
Finally, her hands holding the skirt reached near her waist, and her gray plain panties were revealed.
His gaze, following her hands, met her underwear.
Twitch, twitch.
Unconsciously, the inside of her groin tingled, and she rubbed the inside of her thighs for no reason.
"Aaahh…♡"
Without even knowing why she felt this strange feeling, Vilma's skirt went up even higher.
"A little more. Lift it a little more."
"Yes, yes…"
Finally, her stomach was exposed.
Because she was dressed simply, she was only wearing two pieces of underwear under her one-piece dress. So, below her stomach, the only thing she was wearing was her panties. Her naked body, except for the intimate area covered by thin fabric, was exposed to the boy.
She became conscious of the small amount of belly fat she usually didn't care about.
"That's enough. Just right."
The boy got up from his chair and approached her. And he stretched out his right hand, which was concentrated with mana, towards her lower abdomen.