Soon, Xu Feng returned to Qinglian Sect and briefly reported to Deputy Sect Master Qiu. Xu Feng entered the cave again to retreat and began to study the Six Yang True Fire Refining Heart Lamp! The real big harvest this time was actually the Six Yang True Fire Refining Heart Lamp, which was a complete imperial weapon. Even though Xu Feng had no way to control this Chaos Extreme Spirit Treasure with his current strength, it did not prevent Xu Feng from using the power of this Chaos Extreme Spirit Treasure to practice;

"Counting this Heart Refining Lamp, I already own two Chaos Spiritual Treasures. In other words, I own two small thousand worlds. If this news leaks out, I'm afraid the entire Qinglian Sect won't be able to protect me, unless the Qinglian Sword Immortal comes back at this time!" Xu Feng said to himself.

Two complete small worlds can create two emperor-level strongmen. For the emperor-level peak strongmen, this is absolutely an irresistible temptation. Fortunately, Xu Feng entered the absolute formation by accident, and no one noticed his existence from beginning to end. Otherwise, this stone lamp might not be able to be preserved.

When Xu Feng returned to the cave, he immediately entered the inner space of the Refining Heart Lamp and began to practice the Nine Hells Burning World Demon Suppression Sutra! In the small world of the Refining Heart Lamp, only practicing fire-attributed techniques would be a hundred times more efficient, and practicing other techniques would not have this effect; nine groups of empty shadows appeared behind Xu Feng, and a flame rune loomed in Xu Feng's sea of ​​consciousness. As he practiced the Nine Hells Burning World Demon Suppression Sutra, the true fire in the Refining Heart Lamp began to surge towards this side with Xu Feng as the center. With the blessing of the six true fire rhymes, the proficiency of the Nine Hells Burning World Demon Suppression Sutra increased at an extraordinary speed;

In the blink of an eye, a year passed quickly. During this year, the upper realm did not seem to have changed much. Because Xu Feng was in seclusion, this time the Baimai Xianzong ranking competition was led by Elder Xu Moyun. Because of the use of Hongmeng Tender Bud, Elder Xu Moyun increased his lifespan by 3,000 years, so the Qinglian Sect's ranking slightly improved by two places;

At the same time, in the Six Yang True Fire Refining Heart Lamp, the Nine Hells Burning World Demon Suppression Sutra that Xu Feng practiced also reached an extremely high level. The first three Burning World Demon Suppression Primordial Prisons that opened up the chaotic space had also grown to their limits, and were only one step away from evolving into a small world. From afar, it seemed as if three blazing suns appeared behind Xu Feng, and the light they released even blocked out the six empty shadows next to them. More importantly, during the hundred years of seclusion in the Refining Heart Lamp, Xu Feng also completely absorbed the secret realm into his body, turning it into his own small world. As a result, Xu Feng's cultivation level went from the middle level of the Emperor to the upper level of the Emperor and directly reached the peak of the Emperor. At this time, Xu Feng already had the prerequisites to fuse the Ancestral Dragon Pearl and the Six Yang True Fire Refining Heart Lamp! It's a pity that if Xu Feng chose to fuse the Ancestral Dragon Pearl and the Sun True Fire Refining Heart Lamp and absorb the small worlds within these two Chaos Spiritual Treasures, the moment Xu Feng succeeded in absorbing them and became an emperor-level powerhouse, the Chaos Spiritual Treasure that had absorbed the small worlds would be completely destroyed.

For other peak emperor-level powerhouses, destroying a Chaos Spiritual Treasure in order to become an emperor-level powerhouse is a very cost-effective thing to do. However, for Xu Feng, this loss is a bit too great, because he possesses the emperor-level technique "Nine Hells Burning World Demon Suppression Sutra". As long as he practices this emperor-level technique to perfection, nine small thousand worlds will naturally evolve. At that time, it will be a natural thing to advance to the emperor-level powerhouse, and there is no need to consume any Chaos Spiritual Treasure at all!

"The first three prisons have reached the limit of their potential, and they are only one step away from evolving into a small world!" Xu Feng thought to himself, "If I want to cultivate this technique to perfection, I must build up the remaining six prison spaces. When all nine prisons have been cultivated to the point where they can no longer be advanced, they can simultaneously evolve into nine small worlds..."

“To build the remaining six prison spaces, six spiritual treasures of great fire quality are needed. The resources in the upper realm are abundant, but it is not an easy task to gather six spiritual treasures of great fire quality…” Xu Feng said secretly in his heart.

Being able to obtain three spiritual treasures of great Dao quality with fire attributes was also a coincidence. In fact, even in the Baimai Immortal Sect, only the supreme elders of each sect could possess spiritual treasures of great Dao quality. It was almost impossible for ordinary elders to possess a spiritual treasure of great Dao quality!

Thinking of this, Xu Feng couldn't help but look at the Six Yang True Fire Refining Heart Lamp. This chaotic quality spiritual treasure contained six true fires. Each of these six true fires was enough to open up a world-burning demon-suppressing prison. However, without the spiritual treasure itself to suppress the space, it was not known whether it could successfully open up a prison space with only one true fire. "I still can't fully control the Six Yang True Fire Refining Heart Lamp, and I can't control the six true fires contained in it. It's simply a bit crazy to want to use them to open up six prisons..." Xu Feng suddenly thought that with his current strength, he had no way to control the emperor's weapon. A helpless smile suddenly appeared on his face, and he shook his head to give up this idea. At this moment, the rune in Xu Feng's sea of ​​consciousness, which was condensed by the six true fires, suddenly shone brightly, and at the same time, six true fires were separated, flying towards the six groups of empty shadows behind Xu Feng.

The next moment, with a "boom", the six originally dim shadows in the void were ignited at the same time, opening up six new prisons! Xu Feng's whole body was shocked, and the Nine Prisons Burning World Demon Suppression Qi in his body suddenly increased by 60%. The first three prisons that had been cultivated to perfection and the newly opened six prisons were faintly connected to each other, forming a whole; "The Nine Prisons opened up the Burning World Demon Suppression Prison space at the same time, this emperor-level technique is considered to be perfect..." Xu Feng had a glimmer of enlightenment in his mind. He didn't expect that he could actually open the Burning World Demon Suppression Prison directly with only a true fire and no spiritual treasure of the Great Dao quality. How much effort did this save Xu Feng?

Nine balls of flames burned behind Xu Feng, like nine suns, but the first three looked much bigger than the last six. When the nine flames were as big as the sun, Xu Feng's emperor-level technique, the Nine Hells Burning World Demon Suppression Sutra, would be considered to have been cultivated to perfection! Xu Feng had already reached the peak of the emperor level, and the Nine Hells Burning World Demon Suppression Sutra had now been upgraded to the great perfection level. Xu Feng's cultivation had been greatly improved. Although he had not yet opened up the small world and reached the emperor level, he was much stronger than ordinary emperor-level masters. "I originally wanted to go out and look for the great spiritual treasure of the fire attribute. Now it seems that I only need to continue to retreat and cultivate the last six prisons, and I can naturally be promoted to an emperor-level master..." Xu Feng thought to himself: "If other people knew that an emperor-level master who is less than a hundred years old would be shocked!"