Innate Divine Abilities are merely the most basic state of manipulating Heaven and Earth Spiritual Energy; above them lies Grotto-Heavens.
They not only borrow Heaven and Earth Spiritual Energy but also the power of Heaven and Earth Laws.
The method of borrowing is through Law Charms, which are Spiritual Charms containing Heaven and Earth Laws, usually imbued with a trace of the power of Laws.
Attacks imbued with Law Charms, even the most ordinary techniques and divine abilities, will have incredibly powerful effects.
For instance, a basic fireball technique with a trace of Fire Law Charm could easily kill a Spirit Transformation Cultivator.
This is generally something one only becomes qualified to touch upon after reaching the Void Refinement realm.
Even though it's just a superficial borrowing of the plane's rules, it's enough to cause a massive surge in power for divine abilities.
Ning Fa's expression trembled, filled with pleasant surprise.
Although he had read the Heavenly Mechanism Scroll long ago and was aware of the author's theories, the scroll did not mention the specific division between Innate and Grotto-Heaven states. This was information he had just obtained from the inheritance.
And this special Law Charm of lightning before Ning Fa was a unique feedback he received after advancing to Spirit Transformation, containing a trace of the power of Lightning Laws.
It could allow his Innate Divine Thunder, which had reached the peak of Fourth-grade, to directly advance to Grotto-Heaven Divine Thunder.
Once unleashed, it would be like Tribulation Thunder, capable of containing a trace of Heaven and Earth Law power. Although it was merely a superficial borrowing, its immense power was undeniable.
Only then did Ning Fa understand why his Supreme Metal and Supreme Wood Divine Thunders, despite reaching the peak of Fourth-grade long ago, could not advance. It turned out that this Fifth-grade Grotto-Heaven Divine Thunder was so formidable, making advancement not easy.
As Ning Fa pondered which Divine Thunder to use to absorb the Law Charm and advance to Grotto-Heaven Divine Thunder, a new piece of mysterious inheritance information appeared in his Sea of Consciousness.
Ning Fa closed his eyes to comprehend it. After a full hour, he reopened his eyes, his expression filled with shock.
As expected, after advancing to Spirit Transformation, he had obtained the conditions for advancing to the Void Refinement realm.
And these advancement conditions were far more complex and difficult than advancing to Nascent Soul.
Specifically, it was divided into three steps.
The first step required all five of his Divine Thunders to advance to Grotto-Heaven Divine Thunder, which would undoubtedly be much harder than advancing to Innate Divine Thunder.
The second step was to construct a [Divine Bridge] to connect the five Sea of Lightning Divine Treasuries. The ultimate goal was for the five Sea of Lightning Divine Treasuries to be interconnected through the Divine Bridge, forming a Five Elements mutual generation cycle.
The third step was to merge these five Sea of Lightning Divine Treasuries into one, forming the final Sea of Lightning Divine Treasury, the Chaos Lightning Sea.
This was the Five Elements Unification required for Five Elements Thunder Body cultivators to attempt Void Refinement. Only then would they be qualified to advance to Void Refinement.
Although there were only three steps, each one was incredibly difficult.
First, the advancement of all five Divine Thunders to Grotto-Heaven Divine Thunder.
Although the current Law Charm of lightning could allow one of Ning Fa's Divine Thunders to directly advance to Grotto-Heaven Divine Thunder, he only needed to advance the other four.
However, the advancement of Grotto-Heaven Divine Thunder required specific Law Charms, and these Law Charms must be compatible with the attribute of the Divine Thunder.
The reason the current Law Charm of lightning could be used for any Divine Thunder was that it was a Law feedback, devoid of attributes.
Ning Fa had never heard the term "Law Charm" before, so he had no idea how to obtain them.
But just the fact that it was related to the power of Laws indicated its extraordinary nature, which undoubtedly explained the difficulty of advancing Innate Divine Thunder to Grotto-Heaven.
The second step, constructing the Divine Bridge, although sounding simple, was by no means easy.
This was because the construction of the Divine Bridge required unimaginably precious Spiritual Materials.
It had to follow the principle of Five Elements mutual generation. For example, Wood generates Fire. The Divine Bridge built from the Supreme Wood Sea of Lightning Divine Treasury to the Supreme Fire Divine Thunder Sea would require the Heart Feather of the Nine Yang Azure Luan as its main material.
The Nine Yang Azure Luan was a direct descendant of the legendary True Spirit, the Azure Luan. An adult Nine Yang Azure Luan was at least at the Void Refinement realm, and its heart feather was its most precious possession, a genuine top-tier Sixth-grade Spiritual Material.
The reason it was needed as the main material was that the Nine Yang Azure Luan possessed both Wood and Fire attributes.
It could be said that this single main material alone was invaluable, and even Void Refinement cultivators would find it extremely difficult to obtain.
Furthermore, there were other auxiliary Spiritual Materials whose value, while not as great as the Nine Yang Azure Luan's heart feather, was still immeasurable.
For instance, the Ten Thousand Year Fusang Wood Marrow and the Azure Flame Lightning Dew were also Sixth-grade Spiritual Materials.
The key point was that this was only one Divine Bridge; there were four others.
They also needed to be constructed according to the principle of Five Elements mutual generation, requiring different main and auxiliary materials. However, their grades were generally the same, and their attributes had strict requirements.
The key Spiritual Materials were all Sixth-grade, and Ning Fa had never even heard of most of them.
As for the crucial third step, it appeared easier than the previous two. It involved finding a special location, performing a special ritual, and then beginning the process of merging the five Sea of Light Divine Treasuries into one.
Although the description was simple, it was clearly not going to be easy.
The sheer difficulty and stringent conditions for a Five Elements Thunder Body to advance to the Void Refinement realm made Ning Fa's scalp tingle just thinking about it.
It seemed that after advancing to Spirit Transformation, not only did the strength of a Five Elements Thunder Body greatly increase, but its advancement conditions also became significantly higher.
This made him deeply understand why the Heavenly Mechanism Scroll stated that physiques like the Five Elements Thunder Body or the Mystic Dragon Physique required the cultivation of the entire clan.
However, what brought Ning Fa some comfort was that both the advancement of Divine Thunder to Grotto-Heaven and the construction of Divine Bridges between Sea of Light Divine Treasuries could significantly enhance his strength.
For example, building a Divine Bridge between the Supreme Wood and Supreme Fire Sea of Light Divine Treasuries would not only increase the power of both Divine Thunders but also allow his Supreme Wood Divine Thunder to be arbitrarily converted into Supreme Fire Divine Thunder.
It could be said that every time a Divine Thunder advanced to Grotto-Heaven, and every time a Divine Bridge was constructed, his strength would increase.
Therefore, the process of him seeking to advance to Void Refinement was also a process of gradual strength improvement.
Ning Fa calmed the turmoil in his heart and looked at the Law Charm of lightning before him again. After a moment of thought, he decided to use this Law Charm of lightning for his Supreme Metal Divine Thunder.
Since Supreme Metal Divine Thunder's primary focus is on destructive power, and considering he's a Sword Cultivator whose comprehension of the Sword Dao has reached the third step, once the Supreme Metal Divine Thunder advances to Grotto-Heaven Divine Thunder, it will undoubtedly greatly boost his sword techniques' might.
With this thought, Ning Fa directly opened his mouth and inhaled the lightning dao charm into his body.
Soon, within the Supreme Metal Thunder Sea Divine Treasury he had opened in his lungs, this lightning dao charm manifested and directly merged into the Thunder Sea Divine Treasury that had taken the form of a sharp sword.
The Thunder Sea Divine Treasury erupted with brilliant lightning, and a slightly blurred, small white sword appeared within it, emitting rings of mysterious halos and a unique aura—the distinct aura of Great Dao laws.
Ning Fa reopened his eyes, a look of surprise on his face. He raised his palm, and a bolt of white lightning appeared.
The surrounding Heaven and Earth Spiritual Energy immediately surged towards him. Moreover, Ning Fa could now clearly sense the resonance between this Supreme Metal Divine Thunder in his hand and the surrounding world.
A mysterious rune began to appear on the surface of the lightning. Numerous strands of Heaven and Earth Spiritual Energy poured into it, causing the rune to light up rapidly. This also amplified the power emanating from the lightning to an extremely terrifying degree.
With a soft shout from Ning Fa, this Grotto-Heaven Divine Thunder shot out.
In just an instant, a nearby uninhabited island, hundreds of miles in size, was first enveloped in a fierce lightning glow. Then, everything on the island was directly dissolved by this terrifying lightning. In the blink of an eye, the island vanished.
Even Ning Fa was filled with surprise at this terrifying power.
It truly lived up to its name as Grotto-Heaven Divine Thunder; even without fully utilizing its power, it possessed such formidable might.
He surmised that even a Mid Spirit Transformation Cultivator would find it extremely difficult to resist, requiring them to pay a heavy price.
However, after unleashing this strike, Ning Fa immediately felt a significant portion of his Supreme Metal Divine Thunder depleted.
He estimated that without touching the Divine Thunder Origin, he could still unleash two more strikes of Grotto-Heaven Supreme Metal Divine Thunder.
But he believed no Spirit Transformation Cultivator could emerge unscathed after he unleashed three strikes of Grotto-Heaven Divine Thunder, especially if he were to further activate the Heavenly Law Lightning Realm, which could further enhance the Grotto-Heaven Divine Thunder's power.
With this thought, a smile spread across Ning Fa's face, and the bitterness he felt due to the difficulty of advancing his Five Elements Thunder Body to the Void Refinement realm vanished.
Although the advancement was difficult, the powerful combat strength it brought was undeniable.
Ning Fa had no doubt that even a Late Spirit Transformation Cultivator standing before him would find it hard to be his match.