──Early Morning.
In a Western-style room, a boy sleeping on the bed stirred, eventually sat up, stretched to loosen his muscles, and opened his eyes.
Short black hair inherited from his mother, sharp blue eyes inherited from his father that conveyed a strong willpower. A well-trained, toned physique discernible even through his sleepwear.
The boy saved by Cú Chulainn—his devil name is Leonhardt Pheles, his Japanese name is Kurosaki Renya.
As Renya threw off the duvet, the person sleeping next to him also shifted.
It was a woman.
A young woman was lying down, nestled close to Renya.
Golden hair that reached her waist, an innocently lovely face befitting a beauty. Busty breasts boasting over 100 centimeters, a slender, soft waist, plump hips of child-bearing shape, thick thighs, and a lower abdomen tinged with thin golden curls matching her hair color.
Every part of her body, bearing traces of last night's passion, was exposed without reserve.
This peerless, Italian-style beauty was Lavinia Reni, a witch-girl belonging to the same "Grey Magician" association as Renya and his older childhood friend.
As Renya pulled the thin sheet back over Lavinia, her long eyelashes fluttered slightly, and her eyelids slowly opened.
Her icy blue eyes stared dazedly for a moment, then, upon recognizing Renya, perhaps waking from her sleepy state, she broke into a sweet smile.
"──Leo-kun, good morning."
"Yeah. Lavinia, morning."
Renya replied in a familiar, casual tone. Lavinia also smiled gently, happily narrowing her jade-green eyes. That this short exchange alone conveyed their long-standing, intimate understanding relationship.
Their meeting was eight years ago, when Renya was nine, and Lavinia was thirteen.
Lavinia was born to an ordinary family in a seaside town in Italy. Around age nine, she lost both parents in a mysterious explosion accident. Rejected by relatives due to the supernatural abilities she was born with, she was wandering when she was picked up by Grinda, a witch of "Oz."
After learning magic and about Sacred Gears from her for four years, she transferred to the "Grey Magician" association with the aim of interacting with magicians her own age, which was how they met.
Though their meeting was arranged by Mephisto, Renya—a hybrid devil, an anomalous existence who was an "Extra Demon" and a High-Class Devil yet ostracized from devil society—and Lavinia, similarly adrift from human society, quickly became close due to their similar circumstances and began studying magic together.
At that time, they were just close study friends, but what dramatically changed their relationship was undoubtedly that incident one year later.
Yes, one year after this meeting, Renya was attacked by devils, barely escaped with his life, and met Cú Chulainn. Lavinia's distraught state back then had been something to behold.
Perhaps she thought she would lose Renya like she had her parents. From then on, she became excessively overprotective, even insisting on bathing and sleeping together.
Though tormented by the charms of Lavinia's alluring physique, which had been developing well since around that time, Renya couldn't refuse her genuine affection and concern, accepting it, albeit with internal conflict.
That said, for several years from that point, Renya was like a cute little brother to Lavinia. Their relationship changed to that between a man and a woman happened only very recently.
It started when, several years after Lavinia transferred to the "Grey Magician," her master, Grinda, was attacked by an "Oz" witch and went missing.
A decision was made to dispatch her from the association on a mission to locate and eliminate magicians belonging to the "Wizards of Oz" who were cooperating with the "Utsusemi Agency," while also searching for Grinda.
It began with Renya, who by then had been trained by Cú Chulainn for about three years and possessed considerable strength, accompanying her.
At first, both his parents and Lavinia objected, but his participation was permitted on the grounds of his current strength and the need to cover for Lavinia's... certain lack of common sense—like walking around city streets in broad daylight in her witch outfit.
Since then, while dealing with incidents at their assigned locations, they had encountered "Hounds" and "Four Fiends," and also sometimes cooperated with, sometimes opposed, a boy and girl who hosted Sacred Gears related to a "White Dragon."
However, during the final battle with the "Utsusemi Agency," Lavinia engaged Augusta, an "Oz" witch, but allowed her to escape. During the rematch, shaken by the shock of being rejected by Grinda, Lavinia's body was seized by Augusta.
Filled with intense rage and killing intent, Renya accessed the ultimate, forbidden form of his Sacred Gear and killed Augusta, saving Lavinia unharmed.
Through this incident, Lavinia resolved to meet her master again and speak directly, deepened her trust in Renya, who cooperated with her goal, and simultaneously began to see Renya not just as a reliable, cute junior but as a member of the opposite sex.
After that, various things happened, leading to their current settled relationship.
"Leo-kun? What's wrong?"
As Renya was lost in thought, Lavinia tilted her head curiously and asked.
"...Nothing. I was just remembering the old days with you."
"Ah... D-don't recall too many embarrassing things, okay?"
Lavinia's cheeks flushed slightly at Renya's words as she replied. In the past, she would join him in the bath or bed without hesitation, but at least she had developed more of a sense of shame compared to back then.
──Though she still sometimes slips into the bath or his bed...
She's his senior, yet adorable. That's the kind of woman Lavinia is.
"You were way more incredible yesterday, Lavinia."
"...Honestly, Leo-kun is being mean today. Even though you wouldn't let me sleep last night... After filling me up so much inside yesterday, you're already full of energy again?"
At Renya's words, Lavinia's cheeks flushed a deeper crimson from a different kind of embarrassment.
She spoke with a hint of a pout and bashfulness. Renya lightly kissed her lips.
"Mmm, slurrp... Leo-kun, your cock is already full of energy from the morning."
Lavinia noticed Renya's member tenting the thin sheet and smiled with her reddened face. She used to refer to it in Italian, but after being taught by Renya, she started using the Japanese word for male genitalia, though she still finds it too embarrassing to say any other variation.
"Lavinia."
"Yes."
Just from being called her name, years of companionship allowed Lavinia to understand Renya's desire and comply.
Lavinia let the bedsheet fall away, exposing her beautiful, naked form. Placing her hands on the bed, she crawled closer to Renya.
Then, she brought her lovely face close to Renya's crotch. With her slender, delicate white right hand, she gently grasped the erect flesh-pole and began to stroke it up and down tenderly.