Counting the days, it had taken a full year to repair the damage to his Small Universe. During this period, Yang Kai could clearly feel his foundation declining, which in turn caused his resource refinement speed to be far inferior to before.
He hadn't fought anyone yet—if he actually engaged in combat, his strength would surely drop as well.
A Small Universe was the very foundation of an Open Heaven Realm cultivator. Once damaged, the effects were wide-ranging and multifaceted.
However, the fact that the Sub-Tree had completely repaired his Small Universe within a year exceeded Yang Kai's expectations. That speed was quite fast indeed. He had asked Feng Ying about the effects of consuming the Xuanpin Spirit Fruit, and apparently, even after taking one, repairing a damaged Small Universe would take anywhere from one or two years on the short end to three to five years, or even over a decade on the long end.
By that measure, the Sub-Tree's restorative effect was a notch above the Xuanpin Spirit Fruit.
Not only was his Small Universe now fully repaired, but even the Dragon Pearl that had been damaged during his great battle with Domain Lord Zhufeng had been restored.
In that battle against Domain Lord Zhufeng, Yang Kai had fought with everything he had. In the end, he had been forced to use his Dragon Pearl as a last resort against the powerful foe. Though this move carried tremendous power, it was extraordinarily dangerous. The Dragon Pearl had been severely damaged, and the consequences could have been catastrophic.
In that battle, his Dragon Pearl had been covered in fine cracks.
He had been powerless to repair the Dragon Pearl himself, relying only on his Dragon Vein's power to slowly nurture it back to health. Fortunately, as long as he didn't activate the Dragon Transformation Art, the Dragon Pearl's issues didn't affect his actual combat strength.
Over all these years, without any deliberate effort on his part, the Dragon Pearl had gradually healed under the gentle nourishment of his Dragon Vein's power, returning to its flawless, smooth state.
It was even better than before—the most direct manifestation being that Yang Kai could clearly feel his Dragon Vein's power had improved!
At first, he thought it was his imagination, but upon careful sensing, he found that his Dragon Vein's power had genuinely advanced considerably.
This left him somewhat puzzled.
The Dragon Pearl's gradual repair was within expectations, but the advancement of his Dragon Vein's power was a genuine surprise.
After carefully examining the changes within himself, Yang Kai realized this was a blessing left to him by Zhuozhao and Youying long ago.
Ancient legends held that the Solar Zhuozhao and Lunar Youying were the origin of all Sacred Spirits. The Dragon Clan stood at the head of the Sacred Spirits, the leaders of all living beings, so they naturally shared some connection with Zhuozhao and Youying.
Because of this connection, when Yang Kai had sought help from Brother Huang and Sister Lan due to the Power of Mo, he had been granted those two marks capable of activating the Purifying Light. Not everyone could activate these marks to channel the power of the Yellow Crystal and Blue Crystal into Purifying Light.
If Yang Kai himself hadn't been able to resonate with those two marks, he would have been unable to use them even with the Yellow Crystal and Blue Crystal in hand.
And the first time he left the Chaotic Dead Zone, Brother Huang and Sister Lan had each left a strand of mysterious power within his body.
That power posed no harm to Yang Kai, nor did it help him grow rapidly, but it could stimulate his Dragon Vein's power, making his Dragon Clan bloodline increasingly pure.
It was thanks to the assistance of these two Supreme Beings that Yang Kai's Dragon Vein's power had experienced tremendous growth. When he activated the Dragon Transformation Art before, he had only been able to manifest a thousand-zhang dragon form, barely qualifying as a great dragon. After that, when he activated it again, he could manifest a two-thousand-zhang dragon form—his size had literally doubled.
Yang Kai had felt at the time that the mysterious power Brother Huang and Sister Lan had left within him hadn't been fully consumed, but was dormant somewhere inside him.
For all these years, Yang Kai had no longer sensed that mysterious power.
He never expected that the Dragon Pearl's damage would have quietly awakened that mysterious power, advancing his Dragon Vein's power once more while Yang Kai was almost completely unaware.
Yang Kai didn't know how massive his dragon form would be if he activated the Dragon Transformation Art in his current state, but it would surely be far larger than the previous two thousand zhang.
He planned to find time in the future to experiment with the various changes of the Dragon Transformation Art.
The complete repair of his Small Universe had restored Yang Kai's efficiency to refining one set of seventh-grade resources every six months. His foundation was growing at a remarkably rapid pace.
With this rate of cultivation progress, Yang Kai estimated that in less than a thousand years, he would likely be able to advance to the Eighth Grade.
A thousand years—from Seventh Grade Open Heaven to Eighth Grade. That speed was simply terrifying. After all, at Biluo Pass, there were countless Seventh Grade Open Heaven cultivators who had stagnated at this level for thousands of years without making any progress. Part of this was due to limited talent, and part was insufficient accumulation.
Under normal circumstances, for a Seventh Grade cultivator to advance to the Eighth Grade, no matter how talented, three thousand years of accumulation was the absolute minimum. Normally, it took around five thousand years.
As for advancing from Eighth Grade to Ninth Grade, that was measured in tens of thousands of years. Open Heaven Realm cultivators had sufficient lifespan to complete such a lengthy accumulation process.
Precisely because growth in the Open Heaven Realm was so long and arduous, even though the Grotto-heavens and Blessed Lands had existed for countless ages, there were still relatively few Ninth Grade Ancestor-level powerhouses. No one could guarantee that their growth would be smooth sailing. Even with the potential to reach the Ninth Grade, any accident during the long cultivation process could destroy one's future and cost one's life.
The reason Yang Kai only needed a thousand years was, firstly, that he refined seventh-grade resources during cultivation, which was already extremely efficient. Secondly, the World Tree Sub-Tree in his Small Universe accelerated his refinement speed several times over. Furthermore, he had raised so many living beings within his Small Universe, constantly contributing to the growth of his foundation.
These cumulative advantages combined to allow him to grow in the shortest possible time.
A thousand years was merely an ideal timeframe. If anything delayed him during this period, the years of cultivation would naturally increase.
Maintaining his previous cultivation routine, he would emerge from seclusion for a few days every six months after refining a set of resources, to relax and unwind.