The Underworld.
Inside the Lucifuge clan castle, within a private training field.
"Phew!"
Arlen, having just finished several hours of intense training, felt his reserves of demonic power completely depleted.
He exhaled deeply, letting go of the built-up tension. Sitting on the ground, he pressed a towel to his face to wipe away the sweat, but his gaze drifted upward to the sky—clear as a placid lake—with a somewhat melancholic expression.
He was a transmigrator, and this was his second life.
It was only a few days ago that he had fully awakened his memories from his previous life.
In this life, he was not human, but a hybrid—half-human, half-Devil.
However, during his infancy, he had been adopted by the Lucifuge family from a battlefield, becoming Grayfia's adopted younger brother.
"It can be considered a good start," Arlen muttered with a sigh.
Having a powerful backer like Grayfia and possessing the vast resources of the Lucifuge family for his upbringing, he was incredibly well-positioned.
His strength had already risen to the level of a High-Class Devil not long ago.
For his age, this was considered monstrously strong.
However...
"This world is really a bit too ridiculous," Arlen murmured.
Thinking of the intelligence he had gathered, Arlen's eyelid twitched.
This was a world formed by the fusion of multiple anime series from his previous life.
Just looking at the map of the Human World, one could see one familiar name after another.
Kuoh Town, Fuyuki City, Chiba City... Beneath the calm facade of daily life, countless anomalies were hidden.
Devils, Angels, Fallen Angels, Jujutsu Sorcerers, Exorcists, and Youkai were no secret to a Devil like him.
He had even seen records regarding Taimanin and Heretic Gods.
This made Arlen almost unable to keep his composure.
This world really had a voracious appetite; it dared to fuse absolutely everything together.
"You really are here," a gentle voice sounded beside Arlen's ear.
Arlen turned his head.
A woman with a tall figure and silver hair entered his field of vision
She wore a pure white dress, exuding an air of regal elegance that barely concealed the dangerous intensity lying beneath
She looked like a noble young lady, yet also like a warrior who dominated the battlefield.
The person who had come was none other than Grayfia Lucifuge.
Because of Arlen, her trajectory had long since shifted from the original timeline.
Naturally, she had no need to wear a maid outfit.
"Grayfia-nee, you came," Arlen said with a smile.
He tried to stand up, but his legs were weak from exhaustion, and he staggered.
In the next moment, a wave of softness washed over him, and Arlen felt himself fall into a warm embrace.
Grayfia supported Arlen as he rose, completely disregarding the fact that her intimate action was giving Arlen a distinct benefit.
"You really... you don't need to train so desperately. With me here, no one would dare look for trouble with the Lucifuge house," Grayfia said softly, her tone carrying a hint of complaint as she looked at him.
"I just want to become stronger," Arlen shook his head.
This world truly made people feel too unsafe.
Grayfia was very strong, that was true. She was the Ultimate Queen, after all.
But in front of the top-tier combat power of this chaotic world, she wasn't omnipotent.
Moreover, how could a man hide behind a woman forever?
"My Arlen will definitely become very, very strong," Grayfia said, a gentle smile appearing on her face.
She believed this from the bottom of her heart.
Arlen's training speed, even when compared to the majority of Pure-Blooded Devils, was superior.
Furthermore...
How could the man she had set her sights on be anything less than exceptional?
"Nee-san, can you stop treating me like a kid?" Arlen asked, feeling a bit speechless. "I am already an adult now."
"Is that so? Why haven't I noticed that?"
"Then do you want me to prove it to you?"
As he spoke, Arlen wrapped his arms around Grayfia's slender waist with a chuckle.
"Oh? It seems you want to rebel?"
A blush rose on Grayfia's cheeks, yet she did not avoid Arlen's gaze.
If not for a girl's reserve, she would have confessed her feelings long ago.
"How could I dare," Arlen teased. "It is just that my magical energy consumption is severe, and I wanted Nee-san to provide some mana transfer."
Grayfia froze for a moment.
Arlen really seemed different today.
He had become so bold.
In the past, when she had hinted at mana transfer, he had always been shy.
But today...
Did he really have an epiphany?
Before she could finish the thought, Arlen closed the remaining distance and pressed his lips firmly against hers.
Mmph...
Grayfia's pupils contracted violently as their lips met.
Her mind went blank.
Arlen's eyes flickered as he felt his demonic power recovering rapidly through the intimate contact.
The so-called "mana transfer."
It was a method of replenishing demonic power through the exchange of bodily fluids—in this case, a deep, passionate kiss.
Among Devils, this was a method only used by those who were intimate partners or servants.
"Arlen, tell me the truth... did you go behind my back and mess around with someone else?" Grayfia asked, her eyelashes trembling slightly as she pulled back. She pursed her lips, looking at Arlen with a jealous pout.
"I just have plenty of theoretical experience," Arlen replied without a hint of shame
This was truly his first time performing a mana transfer in this life.
As for other things...
Matters from his previous life naturally had nothing to do with this one.
"Is that so?" Grayfia blinked, and then gave a provocative smile. "Then I need to check thoroughly."
"Do as you please," Arlen smirked.
Arlen and Grayfia gazed into each other's eyes, the atmosphere turning thick and heavy.
Cough, cough.
Just when Arlen was about to lose control, the sound of a deliberate cough came from the doorway.
Instantly, Grayfia jumped to the side like a startled rabbit.
Her ears were bright red, and internally she was panicking.
We're done for.
It's all Arlen's fault.
She actually hadn't even noticed that someone had arrived.
Could it be that everything was seen?
"My, my, it looks like I didn't come at a good time," Rias Gremory said, leaning against the wall with a look of jealousy in her eyes.
Because of the close relationship between the Gremory family and the Lucifuge family, she and Arlen were essentially childhood friends.
Seeing this scene now...
She felt inexplicably irritable.
"Rias, why didn't you say something before you came?" Grayfia said, taking a deep breath to stabilize her emotions and regain her cool composure.
"It's about the favor you asked for," Rias rolled her eyes. "Arlen's admission to Kuoh Academy has been settled."
"You can go and report in soon."
Hearing this, a look of understanding appeared on Arlen's face.
Because the population of Devils was low due to the Great War...
Many Devil families, after the strength of their children reached a certain level, would send them to the Human World to recruit servants and build their own Peerage
"I almost forgot about this matter," Grayfia said, suddenly realizing. She turned her head. "Arlen, I mentioned this to you before."
"You haven't changed your mind, right?"
"Of course not," Arlen nodded.
Regarding this hodgepodge of a world, it would be a lie to say he wasn't curious.
He wanted to know just how crazy the Human World had become.
"Alright, this is your transfer application form," Rias said.
She took out a document and handed it to Arlen.
"When you arrive, you can come to my club and look around. That way we can look after each other."
After explaining a few logistical details, Rias left. Before leaving, she left her contact number, saying he could call her if there was anything he didn't understand.
Noting down the number, Arlen turned his head back to the silver-haired beauty. "Nee-san, now that Rias has left... can we continue?"
Grayfia's expression froze.
Was his boldness always this strong?
She felt like she couldn't handle it anymore.
Even though she had long ago accepted Arlen in her heart, the progress was too fast for her shy side.
"Oh right, I seem to have urgent matters to deal with!"
Leaving behind that one flimsy excuse, Grayfia hurriedly walked toward the exit, fleeing the scene.