Compressing soul power was absolutely exhausting.
Not just physically—but mentally as well.
While cultivating the Inner Core Method and compressing his internal soul power, Ye Yu found that after just over an hour of practice, he was already drained.
He needed proper rest and recovery before continuing.
Fortunately, thanks to the strengthening effect of the Blue Silver Emperor's Right Leg Bone—
And its second soul skill:
"Wildfire Burns Unending, Spring Winds Revive Again"—
Combined with four soul rings from highly regenerative, life-attributed plant-type soul beasts, Ye Yu's recovery rate was extremely high.
As for mental energy—
As long as he wasn't actively compressing soul power and simply cultivated the Inner Core Method, entering that pseudo-Heaven-and-Man Unity state—
His spiritual power recovered very quickly.
And so, throughout the night,
Ye Yu followed a cycle:
Compress for a while → Meditate → Compress again.
Repeating this over and over without pause.
"Ah Yu, how did it go?"
By morning of the next day, Ye Yu finally opened his eyes.
Dugu Yan, her strikingly beautiful and valiant face full of hope, immediately stepped forward and asked.
"I'd say I'm halfway there."
Ye Yu sensed the state of his soul power and replied after a moment of thought:
"Right now, the compressed soul power in my dantian takes up about two-thirds the space it used to."
"I think, with my current physical constitution, I can go further—compress it to about half its original volume."
"That'd be equivalent to someone around rank 23."
He couldn't help but sigh at that point.
Scientifically speaking, he wondered:
How should soul power be explained as a form of energy?
Because he found that—
Once he finished compressing soul power and resumed cultivation,
The soul power he recovered was already in that compressed, higher-quality state.
As if soul power had a memory—
Once compressed, it remembered that form.
At this point, Heaven Dou Imperial Academy no longer offered much benefit to Ye Yu.
After all—
His initial goal in enrolling had been twofold:
To pursue Dugu Yan as a classmate
To access the academy library's rare texts on spirit beasts, soul masters, and—most importantly—life-attributed plant-type spirit beasts
But thanks to his photographic memory,
After nearly two years at the academy,
He had already read and memorized all the valuable materials.
And so, he asked Dugu Yan to help him apply for an open-ended leave of absence.
His next plan?
Continue cultivating at the Ice and Fire Yin Yang Well—
Focusing on compressing his soul power, and also…
Studying the Thunder Body Tempering Technique he won from Yu Tianheng.
He wanted to analyze it, train with it—
And eventually develop his own lightning-based body tempering method.
In the blink of an eye, more than two days passed.
At the Ice and Fire Yin Yang Well, Ye Yu finally compressed his soul power down to his physical limit.
In terms of level (disregarding quality), his soul power was now equivalent to rank 23.
The next step?
Train back up from rank 23 to his original rank 47.
Because his soul power had been compressed,
His cultivation speed was significantly slower than before.
But in the spirit-rich environment of the Ice and Fire Yin Yang Well,
Surrounded by the Blue Silver Emperor Ah Yin and large patches of Blue Silver Grass that he had planted,
Ye Yu essentially had a perfect mimicry training field for his spirit.
Under the guidance of the Inner Core Method, syncing with the world—
His soul power recovery remained relatively fast.
Even better—
The resonance he generated with the surrounding environment also enhanced the cultivation of Ah Yin and the nearby Blue Silver Grass.
Especially the new sprouts.
In this special land, they grew at a pace that would take a year in the outside world, in just a few days.
Once Ye Yu fully restored his compressed soul power back to rank 47,
He retrieved the Thunder Body Tempering Technique manual from his Jade Dragon Bracelet and began to study it.
Frankly, as a self-created soul skill from the Douluo Continent, the training method was quite crude.
It essentially involved using lightning power, converted from the soul master's own soul power, to stimulate less vital parts of the body—like the limbs.
This would allow the body to gradually adapt to lightning energy,
While also increasing control and sensitivity to the transformed lightning.
Once the body adjusted—
One could begin tempering the entire body with lightning.
A critical point in cultivating the Thunder Body Tempering Technique was this:
You had to understand the intensity of the lightning produced by your own soul power.
The manual used the term "lightning pressure" to describe this.
It explained precisely how much lightning pressure should be used in early stages,
And when to increase it after the body reached certain thresholds.
These guidelines had to be followed strictly.
Otherwise—
If the lightning was too intense too early, it could severely damage the body.
But for Ye Yu?
These restrictions didn't really apply.
With the Blue Silver Emperor's Right Leg Bone, and its powerful regeneration effects—
Plus soul rings from plant-type beasts with immense vitality—
His body's healing capacity was on another level.
Not to mention—
The ten-thousand-year Thunder Hell Vine soul ring gave him lightning resistance.
And he even had an external spirit bone: Thunder Hell Spear, capable of absorbing lightning energy.
For Ye Yu, all the so-called taboos of the Thunder Body Tempering Technique were nearly irrelevant.
He smiled.
Then, at the Ice and Fire Yin Yang Well, he began his training.
First, he used his soul power, converting it into lightning energy, to temper his body.
And that wasn't all.
In addition to using converted lightning from his own soul power—
He also had:
His external spirit bone: Thunder Hell Spear, which could release lightning
His third soul skill: Tribulation Ascension, which could summon tribulation lightning directly from the heavens
In other words—
He would never be short on lightning.
Meanwhile, back in Heaven Dou City—
After Ye Yu's transformation—
His dominant display at Heaven Dou Imperial Academy, where he crushed over a dozen classmates on his own—
And even instantly defeated Yu Tianheng, the Blue Lightning Tyrant Dragon Clan's brightest star—
Sent shockwaves through the school.
With word spreading like wildfire among the students,
Ye Yu's name quickly became known throughout the soul master circles of Heaven Dou City.
Given that Ye Yu had entered the academy through Qian Renxue's personal recommendation,
He was—at least in part—considered her person.
When the academy's Three Education Commissioners received the news,
They were stunned.
And they immediately reported the development to Qian Renxue.
After all—
Who would have imagined?
That the young boy who had entered the academy with innate rank-1 soul power, a mere mutated Blue Silver Vine spirit, and at just level 10…
Would, in just two or three years, undergo a complete metamorphosis?
Now a rank-47 Soul Ancestor, defeating Yu Tianheng in one strike?
This kind of genius—the Crown Prince absolutely must not ignore.
(Author's Note: After absorbing the Thunder Hell Vine soul ring, the protagonist's soul power also gained lightning attributes and can now be converted into lightning energy.)