Inuyasha: Building the Dog Demon Soul Society

Kotaro, following the method calculated by the Great Sage, began to circulate his faint demonic energy within his stomach. A warm current emanated from his core, slowly spreading throughout his body.

After about ten minutes, Kotaro felt as though he were soaking in a warm, soothing hot spring. His cells seemed to rejoice, and his entire body felt light and relaxed.

He focused intently on the demonic energy within him.

"Great Sage, can I keep Thought Acceleration active all the time?"

Currently, without Thought Acceleration, his perception of demonic energy was vague and blurry. Activating it would likely make things much clearer.

[Activating Thought Acceleration will place a heavy burden on the host's body. Prolonged use may cause physical damage.]

"What if I use a non-damaging version of Thought Acceleration? Surely I can handle that, right?"

[Analysis complete. The host can sustain a maximum of two times Thought Acceleration without harm.]

Well, that was something. While he could theoretically handle up to twenty times Thought Acceleration, sustaining it continuously was limited to just two times. Still, it was better than nothing.

Activating two times Thought Acceleration, Kotaro immediately noticed a slight improvement in his perception. It wasn't a massive leap—more like going from 240P to 480P—but it was better than before.

Now, Kotaro could sense that the faint thread of demonic energy within him had grown significantly. Previously, it had been as thin as a strand of hair, if not thinner. Now, it had roughly doubled in size.

"It's only been a short while, and it's already doubled? This method is incredibly effective!"

[The calculated refinement method ensures that over 95% of the energy in the mother's milk is perfectly absorbed by the host. Previously, the host's natural absorption rate was less than 30%.]

No wonder the results were so dramatic. The efficiency had more than tripled!

This was excellent. Finally, Kotaro had something productive to do. No longer would he spend his days idly eating, sleeping, and occasionally wandering around before growing tired and repeating the cycle. That kind of life wasn't much different from being a pig.

With such effective results, Kotaro decided to continue. Despite the monotony of controlling the flow of demonic energy, he found it fascinating.

After all, what could be more boring than having nothing to do?

Lying on the bed, Kotaro instinctively rolled over, his fluffy tail curling around his body. He continued refining the energy from the mother's milk, feeling the demonic energy circulate through him. With each cycle, he could sense it growing stronger, even if the progress was slow.

Several hours passed.

Suddenly, a loud growl erupted from Kotaro's stomach. An intense hunger jolted him awake.

He sighed, patting his belly.

"So, I've finished refining the milk, huh? But this hunger is ridiculous! It feels like I haven't eaten in days."

[It is recommended that the host replenish with more mother's milk.]

Replenish? Already?

"How long have I been asleep?"

[Three hours.]

Three hours? That's all?

If this kept up, he'd need to eat eight times a day! While it was normal for infants to eat frequently, this was excessive.

"Can't I eat something else? Like demon beast meat or something?"

[The energy in demon beast meat is not pure demonic energy. Its quality is far inferior to mother's milk and may introduce impurities into the host's body, accelerating physical growth but slowing demonic energy development.]

[It is not recommended.]

So that's why Lady Ryukotsusei hadn't given him solid food yet, even though he was three years old. Raising a demon child was more complicated than he'd thought.

Grrr~~~

His stomach growled again, the hunger unbearable even for his adult soul.

Kotaro kicked off his blanket and jumped down from the bed. His tail, almost as large as his body, swayed behind him as he trudged to the door.

Pushing the heavy door open, he found Lady Ryukotsusei lounging on a long chair in the courtyard, gazing peacefully at the fish in the pond.

Hearing the door creak, she turned her head, her expression one of mild surprise.

"Kotaro, you're awake already? You usually sleep for seven or eight hours after feeding."

Before Kotaro could respond, his stomach growled loudly.

Lady Ryukotsusei blinked, then smiled. "Hungry again? You must be growing quickly!"

She scooped him up, her gentle hands ruffling his hair.

"I need to grow up fast. I can't keep living this embarrassing infant life."

Kotaro ate voraciously, his belly bulging by the end. As he began refining the new batch of milk, Lady Ryukotsusei's eyes widened slightly.

As the wife of Toga and a princess of the dog demons, her powers were formidable, though not quite at the level of a great demon. At such close range, she could clearly sense the unusually active demonic energy within Kotaro.

Her brows furrowed, her moon-like eyes glowing faintly.

"No wonder he's hungry so soon. He's absorbing energy at an incredible rate. His talent surpasses even Sesshomaru's at this age."

"I'll need to eat more, or this little monster might drain me dry…"

Exiting the chamber, Lady Ryukotsusei summoned the dog demon general, Miga, who guarded the royal city.

"Prepare more food for me. I'll need to eat a lot in the coming days. If necessary, capture some demons for me to consume."

Miga was stunned. Eating demons? While it wasn't unheard of for demons to consume each other, it was highly unusual for the dignified princess of the dog demons to make such a request.

"But, Lady Ryukotsusei, if Lord Toga finds out—"

"Do as I say. I'll handle Toga."

***

"Eight meals a day, three hours per meal."

For seven days, Kotarou had been

relentlessly enhancing his demonic energy. Thanks to the Great Sage's refinement method, the results were nothing short of astonishing. In just seven days, he had achieved what would have taken him three years under normal circumstances.

The demonic energy within Kotarou had grown dozens of times stronger. What was once a faint, barely noticeable trickle had now expanded to the thickness of hundreds of strands of hair. This newfound power allowed him to manipulate the flames that naturally burned within him.

The flames danced in his palm, shifting shapes at his will—forming spheres, cubes, and other intricate patterns. For the first time since his birth, Kotarou had gained perfect control over his innate demonic flames.

However, there was a catch. His demonic energy was still relatively weak, limiting the flames' intensity and size. At most, he could conjure a fireball the size of a soccer ball.

Boom!

The fireball exploded against a stone in the garden, instantly reducing it to molten slag.

"Impressive power," Kotarou murmured, a satisfied grin spreading across his face.

"Finally, it's starting to take shape."

He glanced down at his legs, now fully human in appearance. This was perhaps his greatest achievement so far—no longer did he have the furry legs of a dog demon. Though his ears and tail remained, this was a significant step forward.

For three years, he had lived with the body of a beast. Now, for the first time, he could see his own feet.

"Little Kotarou, why are you out here all alone? Aren't you hungry yet? If you are, just tell me!"

The voice of Lady Ryukotsusei, his mother, called out from behind him. Kotarou turned to see her approaching, her graceful demeanor slightly marred by the exhaustion in her eyes.

"Mother, I'm not hungry yet. Don't worry about me," Kotarou replied, shaking his head.

Over the past seven days, Lady Ryukotsusei had visibly lost weight. Eight meals a day were no joke, and Kotarou was beginning to worry about her health. Once a figure of ethereal beauty, she now carried a tired expression, her once-radiant aura dimmed.

Seeing her sacrifice so much for him—spending her days eating, sleeping, and nursing him—had deeply moved Kotarou. Despite his initial reservations about her, he couldn't help but be touched by her unwavering love.

"Mother, you look exhausted. Let me take you back to rest," Kotarou said, tugging gently at her robe.

Lady Ryukotsusei smiled softly, her fatigue momentarily forgotten.

"Such a thoughtful child. You're so different from your brother, Sesshomaru, at your age."

After ensuring his mother was comfortably asleep, Kotarou returned to the garden. He sat on a small stool, his tiny frame dwarfed by the surrounding foliage, and let out a deep sigh.

'This can't go on. While the refinement method is effective, it's taking a toll on Mother's health. Great Sage, can you calculate a cultivation method that allows me to absorb energy on my own?'

[Great Sage: Energy growth is not created from nothing. To enhance your demonic energy, you must absorb energy from an external source. Aside from breast milk, where else do you propose to draw energy from?]

Energy?

'Isn't energy everywhere? What about the energy in the natural world?'

[Analyzing surroundings. Scanning the natural energy in the environment.]

[Requesting full control of the host's body and activation of Thought Acceleration to assist in the analysis.]

'Granted.'

Kotarou was beginning to understand the Great Sage's limitations. While it was a powerful tool, it lacked true autonomy. It required his input to initiate actions, making it more of a sophisticated tool than an independent entity.

[Analysis complete. The host's theory is valid. Energy can be absorbed from the natural world to enhance demonic energy.]

[Calculating absorption methods.]

[Simulating natural environment.]

[Simulation successful.]

[Simulating the host's demonic body's ability to absorb natural energy.]

[Analysis complete. Absorption methods are as follows.]

[Instinctual Absorption: Relying on the body's natural instincts to absorb energy. Efficiency is too low to meet the host's expectations.]

[Demonic Energy Absorption: Demonic energy cannot directly absorb natural energy. Analyzing...]

[Analysis complete. Converting demonic energy into demonic aura to absorb natural energy.]

[Theory validated.]

[Establishing simulation.]

[Converting demonic energy into demonic aura. Absorbing natural energy through demonic aura.]

[Converting demonic aura back into demonic energy. Returning energy to the host's body.]

[Simulation complete.]

[This method causes 50% damage to the host's body. Does not meet requirements. Re-analyzing.]

[Re-simulation complete.]

[Body damage reduced to 43%. Does not meet requirements. Re-analyzing.]

[...Does not meet requirements. Re-analyzing.]

Kotarou's forehead was drenched in cold sweat. With Thought Acceleration pushed to its limit—25 times his normal thinking speed—he could maintain this state for only a few minutes. Prolonged use felt like his brain was on the verge of exploding.

The three-dimensional model in his mind repeatedly formed and collapsed as the Great Sage tirelessly refined the absorption method.

Hours passed, and Kotarou's face grew pale, his body on the brink of exhaustion.

[Calculation complete. Method meets requirements. Zero damage to the host's

body. No further analysis needed.]

[Demonic Energy Cultivation Method successfully created.]

Kotarou's eyes snapped open, a glimmer of triumph shining through his fatigue.

"Success!"

He had finally achieved a way to enhance his demonic energy without relying solely on his mother's breast milk. While the cultivation method's efficiency was only one-tenth of the refinement method, Kotarou was confident it could be improved.

'If I have the Great Sage continuously refine this method—version 2.0, 3.0, even 10.0—its efficiency will undoubtedly increase. Breast milk has a finite amount of energy, but the natural world's energy is limitless!'

With renewed determination, Kotarou leaned back against the stool, his mind already racing with possibilities.

'Starting tomorrow, I'll refine the cultivation method daily. With each upgrade, my growth will accelerate. Soon, I'll surpass the limitations of the refinement method and unlock my true potential.'

***

The garden was quiet once more, the faint crackling of Kotarou's flames the only sound breaking the stillness. His crimson eyes glowed with determination as he gazed at the stars above.

The path to power was long, but Kotarou was ready to walk it—no matter the cost.

T/N: I'm translating this but the other works will be the priority intill they get caught up.