"Ryuuto, how have you been doing lately? It's been three years now since you came to Tokyo—have you properly adjusted to life here?"
The Sajyou family was gathered around the dining table enjoying a quiet breakfast on a sunny morning.
The man speaking from the head of the table was Hiroki Sajyou, a magus dabbling in black magic. Despite his intimidating profession, he was just a gentle, ordinary-looking middle-aged man—the kind you wouldn't look twice at on the street. He was father to the Sajyou sisters.
Ryuuto, sitting at the far end of the table, quickly swallowed a dumpling before answering.
"Yes, I've adjusted well. I really appreciate everything you've done for me, Mr. Hiroki—and Manaka and Ayaka too, of course."
"There's no need to be so formal with us, Ryuuto. I want you to consider this your home now." Hiroki smiled warmly. "Don't you agree, Ayaka?"
"...Yes." Sitting across from Ryuuto, the second daughter—who would be starting junior high next year—gave a slight nod.
At first glance, Ayaka seemed like just a quiet, soft-spoken girl with brown hair. But this reserved, polite demeanor was simply a mask she wore around her father and Manaka, her sister who she always felt she couldn't measure up to.
Whenever Hiroki and Manaka weren't in the room, Ayaka completely transformed—becoming chatty and even somewhat domineering. It was almost like watching Sakura and Rin's personalities crammed into one small body, with Ayaka flipping between them depending on who was around.
Hiroki took a sip of his miso soup and looked at Ryuuto with that gentle, fatherly smile of his.
"You know, if Manaka heard you calling her just by her name like that, she'd probably get upset again, wouldn't she? What do you think about calling me Grandfather instead?"
"No, that's... haha." Ryuuto laughed awkwardly, not knowing how to respond.
After their fateful meeting that day, Ryuuto had become part of the Sajyou family as their adopted son. But there was something unusual about the arrangement—on the official family register, he wasn't listed as Hiroki Sajyou's adopted son at all, but as Manaka Sajyou's.
Ryuuto himself had no idea how a 14-year-old girl could legally adopt a foreigner with no background documents. All he knew was that after Manaka took a trip to the Ministry of Health and Welfare, somehow it was all sorted out. And the other Sajyou family members—Hiroki and Ayaka—also seemed perfectly fine with their new roles as his grandfather and aunt.
'Better not overthink this whole situation,' Ryuuto thought to himself. 'I guess magecraft really does come in handy sometimes.'
Suddenly, a slightly irritated young girl's voice came from the other end of the dining room.
The girl walking toward the two males of the household was breathtaking—almost unnaturally beautiful—with brilliant blonde hair that seemed to glow. Her small frame was dressed in casual home clothes that somewhat resembled a maid outfit, showing off her snow-white skin. Under her short skirt, a pair of slender legs were wrapped in white knee-high socks.
This was Manaka Sajyou—Ryuuto's legal mother.
As a side effect of being consumed and contaminated by the black mud, Manaka's body hadn't changed at all during these past three years.
Though she was already 17 years old, she still had the completely flat chest of an elementary school student.
Standing next to Ayaka who had just started sixth grade, the two actually looked more like twin sisters. In another couple of years, Ayaka would probably end up looking like the older sister.
Manaka walked over to the table with a stern expression and firmly set down a stainless steel bowl filled with broccoli salad in front of Ryuuto.
"Ryuuto, you need to eat this. You never touch your vegetables, and mom is getting really worried about you."
"I think these chive dumplings are... plenty nutritious already." he didn't even glance at the salad as he continued stuffing dumplings into his mouth. "Manaka, humans didn't claw their way to the top of the food chain just to eat plants."
Manaka put her hands on her hips and stuck out her lower lip in a pout. "Since Ryuuto is being so stubborn, mom has another plan—no allowance for you this week."
Ryuuto's back immediately went rigid.
"No allowance? Wait, no, don't do that." He quickly picked up his fork and began tackling the vegetable salad in front of him. "Fine, I'll eat it."
During his time with the Sajyou family, Ryuuto would ask Manaka for an enormous weekly allowance of 1.5 million yen, which he'd somehow manage to blow through in just five days.
But there was actually a reason behind this seemingly reckless behavior.
The Lord said, do not store up treasures on earth, where moth and rust consume. When wealth returns to dust and ashes, the new millennium shall dawn. The seven-headed beast feasts on man's greed, lust, and pride. Only when the golden chalice is emptied and broken shall the gates of heaven part.
You see, Ryuuto was the enemy of humanity Beast of 666's offspring... though he couldn't even be called an offspring or infant at this point—just a larva.
As the larva of the great red dragon with seven heads and ten horns, Ryuuto was constantly fighting against the evolutionary urges inside him. Every moment was a struggle against wanting to kill, wanting to devour souls, wanting to evolve into his complete form, wanting to destroy the world.
To keep these powerful desires at bay, he lived his life in modern Japan much like an ancient Roman emperor might have—indulging in excess at every turn. He frequented nightclubs, bars, racetracks, and pachinko parlors.
Looking back on his time in Tokyo, while you couldn't exactly say he lived in complete debauchery every single night, he had definitely dabbled in all the classic vices—excessive eating and drinking, visiting questionable establishments, whoring, and gambling away small fortunes.
By living this way, he'd actually managed to keep his "appetite" under control—which, in a roundabout way, could be seen as saving humanity.
But that chapter of his life was coming to an end today. Because he was planning to participate in the Fourth Holy Grail War being held in Fuyuki.
His goal wasn't to actually get his hands on the Holy Grail—he just wanted some entertainment. Becoming someone who chases after fun and excitement was simply how a Beast tried to exist in modern society.
"I'm heading to Fuyuki today for some final preparations for the Holy Grail War," Ryuuto casually mentioned to Manaka beside him.
The girl immediately looked worried. "What? Why didn't you tell me earlier? If I'd known, mom could have prepared a bento for you to take along."
"That's exactly why I waited until this morning to mention it," he snorted. "Mom... Seriously, I'm not some kid going on an elementary school field trip."
"Ryuuto! Did you just call me mom?!" Manaka's eyes suddenly lit up as she grabbed his arm and shook it excitedly.
"No, you misheard me."
"You totally did! I heard it with my own ears!"
"...Hahaha."
Watching the two of them bicker at the breakfast table, her father could only offer a helpless smile, while his middle school sister deliberately avoided looking in their direction.
"Ugh... Ryuuto is being so stubborn again. Now mom is really upset." Manaka crossed her arms and stuck out her lower lip in an exaggerated pout.
Ryuuto set his chopsticks down on his plate and pressed his palms together. "Thanks for the meal. I'm done."
Hiroki looked up from his own breakfast. "By the way, Ryuuto, since you're heading to Fuyuki, please give my regards to Mr. Matou when you see him."
"Will do, Mr. Hiroki."
Ryuuto stood up from the table and glanced at Manaka, who was still visibly sulking. He placed his hand on her silky blonde hair and gave it a gentle pat.
"...Hmph." The girl whose head was being patted narrowed her eyes and puffed out her cheeks. "If you think Manaka is the type of girl who can be so easily appeased, you're seriously mistaken..."
"I'll be back before dinner tomorrow," he said, then paused for a moment before adding, "You know, I've been having this craving for squirrel fish lately, but none of the Chinese restaurants in Tokyo seem to capture the authentic flavor."
He hesitated just long enough before saying, "Do you think you could make it for me, Mom?"
"O-Of course! Leave it to me! Mom will make you the most delicious squirrel fish you've ever tasted!"
'She's so ridiculously easy to please,' he thought to himself with a smile.