Fang Tianyou stayed in the cave for another seven days. For seven days, Fang Tianyou used the Flying Immortal Hu to absorb the evil qi in the cave, and at the same time, he practiced his previous conjecture of turning the mountain boy into a perpetual motion machine.

After cultivating the mountain boy into the instrument spirit of the Flying Immortal Hu, Fang Tianyou imagined that after transforming the mountain boy himself into the "Yin Evil Knife", after slashing at the enemy, he could radiate a yin evil aura, find his home, and return to the Flying Immortal Hu.

In this way, there is no need to consume the yin evil qi at all, and it can continuously send out the "yin evil knife", which is completely a perpetual motion machine, like a heavy blow gun that cannot be filled with bullets.

When he came back from the island country, Fang Tianyou had been trying this aspect in addition to cultivation, but every experiment had to waste a lot of evil qi, and the evil qi absorbed by the Flying Immortal Hu itself was limited, so Fang Tianyou didn't dare to try it with all his might.

Now that there is enough evil qi in the cave, this gives Fang Tianyou a superior experimental field to fully carry out experiments. After seven days of experimentation, the mountain boy was already able to transform his energy close to the ninth layer into a "Yin Evil Knife".

As long as there is more than a layer of evil qi left in the Flying Immortal Gourd, it can guide the "Yin Evil Knife" after being cut out to re-transform into Yin Evil Energy and return to the Flying Immortal Gourd.

In this way, after cutting out, the consumption of yin and evil energy is less than half a layer, which is close to the ideal state of Fang Tianyou's perpetual motion machine. It's just that if you want to not consume it at all, if you want to transform all the mountain boy's energy into a "Yin Evil Knife", you still need to further cultivate.

It is not easy to achieve such a perfect place, the more you go to the back, the more difficult it is to cultivate, and it still needs a certain opportunity, Fang Tianyou estimates that it will not be able to complete it in a month or two, so he dispelled the idea of continuing to cultivate the "Yin Evil Knife".

Fang Tianyou was also very satisfied with the current state of the Flying Immortal Hu. The mountain boy is even more powerful, and with his own soul body alone, he can almost compare to the mountain boy who was under the Yasukuni Shrine at the beginning, and if he uses the "Yin Demon Knife", the power is even more amazing.

Under the urging of Fang Tianyou True Yuan and the evil qi in the cave, the Flying Immortal Hu was further activated. The cyan body is enlarged twice, and the whole body exudes a metallic luster.

What's more, the huge flying formation in the Flying Immortal Hun and the Eight Desolate Yin Evil Formation composed of eight strange and mysterious magic seals have all been strengthened, and the flight ability, the speed of absorbing evil qi, the formation of the "Yin Demon Knife", and the power of the attack have been further enhanced.

Now, from absorbing evil qi to releasing the "Yin Evil Knife", theoretically it only takes one day to complete, and it is no longer like before when it takes ten days and half a month to slowly cultivate before to form the "Yin Evil Knife".

Moreover, with the strengthening of the Eight Desolation Yin Evil Array, Fang Tianyou found that the Flying Immortal Huzhong could not only store one "Yin Evil Knife", as long as the evil qi was enough, it was theoretically possible to cultivate eight "Yin Evil Knife".

In seven days, most of the evil qi in the cave was consumed and absorbed, in addition to the benefits of the Flying Immortal Hun and the Mountain Boy, Fang Tianyou also stored a "Yin Evil Knife" in the Feixian Hu.

In addition to studying the "Yin Demon Knife" and the Flying Immortal Gourd, Fang Tianyou also tried to plant the Demon Soul Flower here. When I first got the Eight Mirrors of the Mountain Boy, I found thirteen seeds of Demon Soul Flowers in the inner space.

The Demon Soul Flower is one of the best medicinal materials for refining soul power elixirs, and the effect is even better than that of the Soul Cleansing Vine. Mature Demon Soul Flowers can not only refine the Soul Nourishing Pill, but also refine the Soul Nourishing Pill with a better effect.

It's a pity that the cultivation requirements of the Demon Soul Flower are extremely demanding, and it needs to be in a dark place where the evil qi is extremely heavy and there is no sunlight to sprout and grow, and Fang Tianyou has not been able to find a suitable opportunity to try planting.

This time he found a suitable environment in this underground, so as soon as he arrived at the cave, he planted the seeds of thirteen demon soul flowers.

In seven days, five seeds sprouted. Although it was not 100% surviving, this also made Fang Tianyou feel very satisfied. It is very difficult for the Demon Soul Flower to germinate, but once it sprouts in a suitable environment, it will hardly take much trouble to grow in the future, so Fang Tianyou decided to let these five Demon Soul Flowers grow here, anyway, this is underground, and it is generally impossible to come.

The remaining eight seeds, Fang Tianyou did not waste them, and refined another furnace of Soul Nourishing Pill. With the Soul Nourishing Pill, Fang Tianyou took this opportunity to repair his Origin Soul again. Distinguishing the soul clone is somewhat damaging to the origin soul.

In Chixia Village, he absorbed the Demon Soul Dark Bamboo, although he also repaired his divine sense a little, but it was not completely repaired, and now that the Soul Nourishing Pill was enough, of course Fang Tianyou no longer allowed any flaws in his soul.

In addition to the Origin Soul, Fang Tianyou also let the soul clone, the Little Golden Man, devour a Soul Nourishing Pill to further strengthen the soul body. Although the soul clone is still not strong in combat, it can stay outside for a longer time, and the speed of self-absorption of soul power has also accelerated a lot.

What should be done has been done, and Fang Tianyou returned to the ground. Fang Tianyou did not continue to absorb the small amount of evil qi left in the cave, but let them stay, so that the Medicine King Valley Seven Evil Array could continue to operate.

As for the Earth Evil Stone, Fang Tianyou only took two pieces as a presupposition, and the remaining one was left in the ground as a seed of evil qi to continue to gather the evil qi underground.

Although Fang Tianyou had already confessed, when he appeared in the Medicine King Valley again, Lu Jialuo and the others breathed a sigh of relief. In the past few days, they have studied the alchemy experience given by Fang Tianyou, and there are still some incomprehensible points, and they are about to ask Fang Tianyou for advice.

All of this was of course expected by Fang Tianyou, although the refining pill of the Medicine King Valley was a must-have in Huaxia, it was not at all compared to the Immortal Cultivation Realm.

It is Fang Tianyou's experience in teaching the secular sects of the immortal cultivation world and writing it at will, for Lu Jialuo and the others, it is also very mysterious, without Fang Tianyou's guidance, they are only afraid that it will take three years and five years of experiments to study thoroughly.

What surprised Fang Tianyou was Song Qiuyue and Fu Huiyan behind Lu Jialuo and the others. They should be waiting in Chixia Village, how could they come to the Medicine King Valley. Fu Huiyan saw Fang Tianyou's gaze, and then walked over with Song Qiuyue.

"You have been here for more than ten days, Song Qiuyue is not at ease, she wants me to bring her over to see, I can't help it, so I have to bring her here. Fu Huiyan explained.

"I, I ......" Song Qiuyue saw that Fang Tianyou was fine, she was overjoyed at first, and when she heard Fu Huiyan's words, her face suddenly turned slightly red, I don't know if it was because of embarrassment, "I" was for a long time, and I didn't know how to excuse myself.

"I said it would be fine, but you still don't believe it. Fang Tianyou hurriedly answered and comforted, but his heart was also warm. You must know that Song Qiuyue came to investigate, and she had to take some risks.

If Fang Tianyou was trapped by the Medicine King Valley, then with Fu Huiyan's ability, it would be impossible to save people, even Song Qiuyue herself would be difficult to get out, after all, Lu Hongen's death had nothing to do with her.

Fortunately, Fang Tianyou was fine, and he successfully recovered the Medicine King Valley, so Lu Jialuo and the others had to be polite to Fu Huiyan and the others.

When the people in the Medicine King Valley saw Song Qiuyue's attitude, they immediately understood something. Song Qiuyue and Fang Tianyou have a close relationship, but Lu Hongen is the head of the word "color", and he actually wants to rob Song Qiuyue, didn't he hit the muzzle!

When Lu Miao'er saw Song Qiuyue and Fang Tianyou's conversation, she didn't know why, the expression on her face was a little complicated, and she looked at Song Qiupeng's eyes and was even a little jealous.

"Everyone, let's take a seat in the main hall and talk. Miss Song has been here for a day and a night, and she is so focused on remembering the real person that she refuses to eat a meal from our Medicine King Valley. The Great Elder also hurriedly came out to play the round.

When Song Qiuyue heard this, her face turned even crimson.

"I've been cultivating in a secluded place during this time, and I'm also hungry, so let's go and have a good meal. Fang Tianyou said with a smile.

After staying in the Medicine King Valley for one more day, Fang Tianyou instructed Lu Jialuo and the others to refine the medicine. At the same time, the Seven Evil Formations were improved and strengthened.

After all, there are now five Demon Soul Flowers planted under the ground of the Medicine King Valley. Let the Medicine King Valley strengthen its defenses to better protect the Demon Soul Flower.

The next day, Fang Tianyou was ready to take Song Qiuyue to leave Taihang Mountain and return to the secular world. Fu Huiyan returned to Chixia Village on her own. Lu Jialuo arranged for Lu Miaoer and Elder Zheng to drive a helicopter to send Fang Tianyou and Song Qiuyue out of Taihang Mountain.

Fang Tianyou did not refuse. Originally, now that the Flying Immortal Hu is strengthened, it is not a problem to fly with another Song Qiuyue, but the consumption will be a little more. Now that the Medicine King Valley is going to be delivered, of course he has to save some effort.

Lu Jialuo didn't know what the considerations were, when arranging the position, he directly arranged Fang Tianyou to the middle of the back row, with Song Qiuyue sitting on the left and right, and Lu Miaoer sitting on the right.

In this regard, Fang Tianyou didn't say much, but Song Qiuyue seemed to see something, and a trace of displeasure flashed in her eyes, fortunately, seeing that Fang Tianyou didn't look at Lu Miaoer much, she felt a little more comfortable in her heart.

Fang Tianyou didn't talk much, and Song Qiuyue was originally an active and talkative person, but because Lu Miao'er and Elder Zheng were there, they didn't talk much.

However, Elder Zheng seized this opportunity to ask Fang Tianyou about the alchemy method without saying a word, and Lu Miao'er also took the opportunity to interject and ask.

Song Qiuyue saw that she couldn't interject, so she also took the initiative to speak, diverted the topic, and chatted with Fang Tianyou about something else. Seeing this, Elder Zheng and Lu Miao'er did not force it, and occasionally interjected to talk about worldly matters.

In this way, the atmosphere on the plane was much calmer, and the four of them were able to pick up occasionally. When the plane flew out of Taihang Mountain, the relationship between Song Qiuyue and Lu Miaoer improved a lot, and they also agreed to take Lu Miaoer to the mall next time they had time.

"I want to cultivate too!" As soon as Elder Zheng and Lu Miao'er left, Song Qiuyue immediately pulled Fang Tianyou's hand and pouted.

"Isn't your father a martial artist, if you really want to cultivate, you won't wait until now, right?" Fang Tianyou said suspiciously.

"I didn't want to learn before, but now I want to learn, I want you to teach me, you can't teach me!" Song Qiuyue said, her slender hand had already pinched a piece of meat in Fang Tianyou's hand.