The diagram circle around Dylan was constantly supplying medicinal essence for him to quickly recover from the immense physical pain and mental stress caused by the breakage of his Spirit Core. It is called the Minor Heavenly Refining Formation which Cosmic God acquired from a quest when he just started cultivating.
...
The Cosmic God had the Breaking Evolution theory when he was young. This theory was inspired when he saw how an eccentric God-level Blacksmith destroying the core of an Immortal-level treasure and using the Greater Heavenly Smithing Formation, to restore the core. He saw how the core was undergoing an evolution after the first cycle and the same happened for the latter cycles.
He believed that if the core of a treasure could evolve through the use of this breaking-restoring cycle, then the same principle could be used to the spirit core of a cultivator!
He searched for a Formation Master and request a formation to create a version of the Greater Heavenly Smithing Formation that would be appropriate for energy refinement. The Formation Master requested a quest in exchange. If he could complete it, then he would create the formation he wanted. Fortunately, he was able to finish the quest and was gifted the Minor Heavenly Refining Formation which was easy to set up even for cultivator without any knowledge of formations.
When he inscribed this method on the Legendary Core Chapter, he also left a warning to beware of the unimaginable pain the user would experience.
...
Luckily, this was already his second time experiencing such torture. But despite knowing the intensity of the pain, Dylan could barely hold together his consciousness.
This type of pain was not the type of pain which was only abrupt and lasts for a single moment. This type of pain sends wave after wave on the brain down to the nerves as it cyclically flows around the body indefinitely. It lasted for only two minutes but those two minutes were like going to hell to experience it's punishment. It may have seem short for others but it felt like eternity to Dylan.
"Fuck this! It fucking hurts!" Dylan cursed when the pain diminished. He was heavily panting and sweating profusely by the time the pain died down. He had coughed blood 5 times within 2 minutes. He unintentionally remembered the torture that Byron did to him. The pain back then was just as horrendous as the pain he was currently experiencing.
He could only grit his teeth and constantly telling himself that all of this is for the power he was seeking. To relieve his body from the pain, he was madly absorbing the medicinal essence from the circle and redirecting it to his destroyed Spirit Core.
Dylan was redoing the method mentioned in the Legendary Core Chapter. Back when he was at the lake, he used the power of the Cosmic light in order to rebuild his broken foundation. Thanks to that, he was able to easily restore his cultivation.
Now, he needed the herbs to alleviate the pain and restore his foundation but as for his cultivation, that would be a different story. Dylan would need to start back from square 1 since he doesn't have the Cosmic energy to restore his cultivation anymore. Despite knowing its downsides, Dylan still chose to persevere and continue down this path. He will rebuild his cultivation from scratch and create the godly spirit core and spirit veins of the Cosmic God.
"Now, it's time to reform my spirit core." Dylan weakly said.
His foundation was then reformed into an even wider and tougher foundation base. Dylan could estimate that his current Spirit Core which was broken twice is capable of containing twice the amount of energy he could previously absorb. He tried absorbing energy from a spirit stones and noticed that the rate of refinement was at least twice his previous speed.
"Amazing! It truly is worthy of being called legendary!" Dylan was delighted as he discovered the upgraded version of his Spirit Core. He suddenly felt that the pain he experienced was all worth it. His eyes burned with resolve as he prepared another two batches of the herbs and placed in on the diagram below him.
"Again!" Dylan gritted his teeth as he prepared for another wave of excruciating pain that was delivered by the breaking of his upgraded spirit core. Helpless as he was, another roar of anguish resounded.
"ARRRRRGHHHHHHH!! GRAAAAAAAWR!!!"
His body was developing an instinctive fear against the pain but Dylan did not let his mind break from the pain as he held on to no matter how little of his consciousness he could. Breaking the upgraded version was harder than breaking it previously and the same went for the amount of pain he felt since it was more sturdier and faster than it once was.
"The pain... *pant*... just freaking... *pant* *pant*... increased... *pant*... Blurgh.." Dylan coughed blood a dozen times this time around. After two minutes of hellish torture, Dylan was breathing with his shoulders and was deathly pale. He did not expect that the pain would actually increase. Due to shock from the damage he received, he almost lost his consciousness.
Dylan could not lose consciousness while his spirit core is destroyed because if he did, it would be no different than dying. With the spirit core destroyed, the spirit veins would not have any container despite absorbing energy involuntarily.
Inconspicuously, the blood he coughed was being slowly absorbed into the diagram. Dylan was too focused on recovering that he did not see this detail.
He greedily absorbed the medicinal essence from the diagram and eliminated the pain physically and mentally. After recovering, Dylan used the essence to restore his spirit core and reinforced it with the essence. He was only able to successfully do it after two hours which was twice the amount of time he used to restore his spirit core earlier.
When the reinforcement was done, Dylan discovered that the spirit core has been upgraded yet again in terms of capacity and toughness. However, he was not as happy as he was the last time because the pain he felt almost killed him. Thanks to this, he readjusted his mindset and prepared for even more pain to come.
He did not let himself be swallowed by the fear caused by the pain as he resolutely tried to break his spirit core once more. For his fourth time, the process of breaking the core became even more difficult as the pain he felt was lasting about five minutes now.
"AAAAAAARRRRRRRRGGGGHHHHHHHH!!"
"GRRRAAAAAAAAAAAAAAAAWWWWRRRR!!!"
Dylan was letting out different roars one after the other. He has coughed two dozen times during this five minutes of torture. Despite his strong willpower, he nearly fainted during the fourth breaking of the core. After some moments of catching his breath, Dylan proceeded in the reconstruction of his Spirit Core which took an even more lengthy time of 4 hours.
When he tried breaking his 4th time reconstructed spirit core, Dylan was subconsciously shivering with his body. His body could no longer handle the pain of breaking and restoring his spirit core. It has developed a fear from the pain and wants Dylan to stop this arduously torturous training.
Dylan looked on his shivering palm. He was not moving it but it was involuntarily doing this. Dylan bit his tongue and balled his fist as he increased the intensity of his grip.
"I have already come this far! I'm just one refinement away! Just this pain won't stop me!! I'll definitely become stronger!!!" Dylan resolutely said while he relaxed his bleeding fist which was bleeding due to his nails digging deep until blood came out.
Dylan closed his eyes and broke his spirit core once more! This time it took him a whole 10 minutes to fully destroy. During this period, sweat dripped down from him like rain and he shouted on the top of his lungs no longer sounding the a human. Tears were subconsciously flowing down his tightly closed eyes.
"Got... to... HOLD ONN!!!!!"
There had been more than five times where his consciousness nearly faded but he bit his tongue the same number of times as so. Blood started dripping from his mouth at the second time time and his clothes was then drenched with blood on the fifth one. He couldn't count how much blood he coughed on the floor, he only tried to hold on as much as could.
Those 10 minutes were as long as 10 years for Dylan but eventually his tenacity paid off when the pain subsided! It was at this moment that his spirit core was undergoing a breathtaking transformation!!
As Dylan was guiding the medicinal essence to his spirit core, the spirit core was evolving to a gold-colored spirit core! Unlike the first three reconstructions he had done, this transformation was near instantaneous!! His skin had a golden hue to it while his hair became similar to golden silk! Dylan was emanating golden lights while his spirit core evolved to the Legendary Core!!
...
Outside the cave...
Spirit beasts were either hiding in their habitats or running/flying away from the cave. The cave was releasing gold lights which brightened the night sky.
A group of hunters were roaming around trying to find beasts to slaughter and bring to the city. They too noticed the blinding gold light that was being emitted from the cave.
"Boss, what's that?!" A grunt asked in fear. From all the years that they have roamed this forest,something like this has never happened before.
"I don't know." The burly and hairy man who only wore pants and exposed his hairy upper body. His orange hair covered his back and his beard covered his jaw and neck. His chest hair was covering not only his pecs but also his belly. He looked like a savage lumberjack while he carried an axe on his right hand.
"But it has got to be a high level spirit beast to cause such a phenomenon to happen! Hahaha it seems like we have hit the jackpot boys! Come on! Let's head to where the light is coming from!" The burly man raised his axe and lead the group to the origin of the light.
"Aye!" The more than a dozen hunter cheered as they followed.
...
"Hahaha!! I have finally done it! I have achieved the Legendary Core!!" Dylan celebrated happily.
His body was also experiencing a substantial change! He felt that his body was as light as a feather and his arms had the strength of 20 men! This was without the use of spirit energy!
"I feel incredible! This feeling made all those pain worth it! Wahahaha!" Dylan jumped joyfully as though he did not experience the torturous training he did during this 8-hour period.
"Hm...?!"
Dylan was just about to get a Primal Stone from the mansion when he saw the diagram below him shining in the color of blood! It was far different than the white glow it had earlier.
"What the heck is happening here?!" Dylan was stunned when he saw the bizzare occurrence that was happening. This event was not stated within the manual so Dylan was wondering what on earth was happening right now?
The diagram was intensely shining and was absorbing the natural energy around it as though it wanted to devour something. Dylan found this strange as a strange idea popped into his mind.
"Blood? Could it be...?" Dylan questioned himself. He felt that he suddenly understand what was currently happening.
"It's not like I'll lose anything. Here goes nothing!" Dylan gambled as he retrieved the other two batches of medicine on his hand and placed it to their places.
Strangely, the moment Dylan placed the first batch of the herbs, the diagram immediately devours the energy from it!
"What?!" Dylan was definitely shocked when he saw this happened. But he still chose to continue and supplied the other batch to the diagram. However, the diagram devoured the herb as well but in a slower rate. It seemed like it can still eat more.
"Should I also give it the last batch I have?" Dylan contemplated. After some thought, Dylan also supplied the last batch he had. It was slowly absorbed and the diagram shimmered in bloody light intensely!
"The Minor Heavenly Refining Formation is said to be capable of doing 5 refinements before resulting to disablement. That's why the Cosmic God used this to support his theory of the Legendary Core which is to break and restore the spirit core for evolution and succeeded. My blood has also done something strange to the diagram. Maybe it's due to me being a descendant of a True King?" Dylan speculated.
"A True King is blessed by the power of the Harmonic Convergence or the Six Cloud Convergence which is a natural phenomenon birthed by the heavens. Thus, it would not necessarily wrong to say that it is of heavenly blood. Heavenly blood affecting a Heaven Rank formation is feasible in this sense." Using this logic, Dylan felt his deduction was right.
"Since I have only done the refinement four times means that I can still conduct another refinement!" Dylan seriously said.
He strengthened his resolve! If what he was thinking was right, then he would have a spirit core that is even stronger than the Cosmic God himself! His situation was different from the Cosmic God because before he could use the 5 refinements of the Minor Heavenly Refining Formation, he received the blessing of the Cosmic Light which meant that if he uses the rest of the diagram, he would have 6 refinements of the spirit core! This would create a never before seen upgraded version of the Legendary Core!!