This time back to the sect, Shan 13 simply dealt with the affairs of the outer hall and announced the retreat. The whole person devoted himself to the soul fire, not only the question of the soul fire promotion, but the follow-up exercises of the "Bone Classics and Marrow Sutra" because of the growth of the soul fire.

"Bone mound?"

At this moment, the "Bone Classics and Marrow Sutra" undoubtedly gave Shan Thirteen another shock, it turned out that the skills he had mastered were all in vain, and there was no substantial power.

The most important thing is that the bone qi is only free in the bone veins, and does not form a storage location similar to the dantian, and can only be refined from the outside world.

The reason why it is difficult to use the Heaven Shaking Lore is that on the one hand, this lore does require a lot of backbone, and on the other hand, the foundation of the thirteen bones of the mountain is too small, and the total amount of backbone is limited.

It's not that bone cultivation can't store bone energy, but the realm of Mountain Thirteen has not been reached, and at this moment, because of the leapfrog advancement of soul fire, he knew the answer in advance, and the dantian of bone cultivation has a strange name - bone mound.

The bone mound is different from the dantian that has a fixed position, but allows the bone cultivator to choose one of his own bones, as long as he can withstand the tempering of the soul fire, it can be completed.

"Whatever bone you want, wouldn't it be impossible for the enemy to attack!"

Shan 13 couldn't help but feel a burst of joy, the Achilles heel is not in the imagination of ordinary people, isn't it a few more points of chance of winning in battle, this person who created the exercises is really talented!

"However, it is really not easy to refine the bone mound!"

Shan Thirteen, who was excited just now, saw how to refine the bone mound, his face couldn't help but sink, the price was too great: a first-grade soul fire, a thousand-year complete skeleton, these two are ready-made, and they are also of high quality.

But the next few things are really rare: a four-grade demon beast essence blood, a three-thousand-year-old mandala, and a wind and thunder attribute spirit stone.

"The immortal method is the immortal method, and it is not the cabbage on the side of the road, it is a little difficult and normal. Shan 13 comforted himself, it's better to get the soul fire done first.

The sea of souls is no longer a white expanse, but there is a lot of faint mist floating in it, and it goes without saying that these are the essence of the Blue Pupil Beast Flame.

The most conspicuous of them was a flame shaped like a pupil, although it was less than the size of a tenth of a fingernail, but that unruly aura ignored the burning of the ice light osteitis.

"The body of the blue-eyed horned cow is still there, and it is naturally impossible to refine it, so let's seal it first. ”

Shan Thirteen thought of the blue-eyed horned cow that was taken away by them by the thunder, and he didn't feel a feeling in his heart, the second-grade soul fire and the third-grade soul fire, but there was a world of difference, which undoubtedly greatly delayed the effect of his bone rune bone weapon refining.

In the following days, Shan 13 became a frequent visitor to the side of the sect leader Yun Potian, and the meeting was to urge some things, which provoked Yun Potian to cancel the sect meeting several times.

"Sect Master, you're not interesting enough, right? One pill of Four-Rank Pei Yuan Pill is enough for your daughter to advance to the middle stage of foundation building, could it be that she is not qualified enough?"

Shan Thirteen looked like a little deflated three at this time, and after several requests for help with heavy bleeding, he finally gathered three thousand years of mandala and wind and thunder spirit stones, but the essence blood of the four-grade demon beast was too precious.

"I'm not only a father, I'm also a master, but also a sect master, who do you say to a four-grade Peiyuan Dan, it's not for me to offend people, you can figure it out. ”

Yun Potian seized the opportunity, his face was even more cunning than that of Shang Jia, and finally at the price of seven four-grade Pei Yuan Dan, he sold a bottle of demon beast essence blood, although it was rare, but the grade was enough.

Ten days later

Shan 13 entered the most hidden ashram of the sect, and in order to refine the bone mound safely, he even did not hesitate to disturb the old sloppy man in retreat, and warned that no one should approach.

The refining of the bone mound is divided into three steps: the pregnancy mound, the refining mound, and the quenching mound, and the gestation mound is the most critical step, if the pregnancy is not successful, everything is in vain.

In the blue ribbon space, with the nineteen skeletons of more than a thousand years or more that had been collected in the past, Shan Thirteen carefully examined them one by one, and finally locked his eyes on a humanoid skeleton.

With a move of his hand, the bones appeared in front of him, and according to the method of the pregnant mound, the essence blood of the four-grade demon beast was smeared on each bone little by little, and then dried it with soul fire.

The bones that had absorbed the blood of the four-grade demon beast seemed to become bright, and the thirteen mountains did not stop for a breath, with a move in their hands, the spirit stones of the two attributes of wind and thunder were embedded in the pupils of the bones.

"Ice light osteitis, points!"

In the sea of thirteen souls of the mountain, the ice light osteitis was divided into two, and this soul split almost made the consciousness collapse and turn him into an idiot.

"Hey!"

Enduring the pain of torn souls, Shan Thirteen's fingers pinched three seals in a row, and slowly injected the split half of the ice light bone into the skull.

Ooh......

As soon as the ice light osteitis entered the skull, a strong resentment suddenly came to his face, frantically resisting the invasion of the ice light osteitis.

"The wind is thundering!"

At the same time as the Ice Light Osteitis entered, Shan Thirteen's backbone was not idle, but tightly wrapped the Wind Thunder Spirit Stone, and when the resentment appeared, it quickly released the true qi of the Wind and Thunder Attribute.

Yes......

A terrible scream rippled in the soul, making the suffering of the splitting undoubtedly worse for Shan Thirteen, his hand shook slightly, and the bones and skulls were lifted out of a piece of broken bones.

Swish......

Shan 13 grabbed the broken bones and put them back, at this time the bones were ignited from the inside out, and the moment Shan 13 touched it, he saw a large piece of skin and flesh instantly turned into ashes.

"Super high fire temperature!"

Shan 13 looked at his bare fingers with some surprise, looking at the bones wrapped in the raging firelight, and with a slap of his hand, the three thousand years of mandala were evenly scattered in the firelight.

Boom......

However, in a moment, the raging flames turned into a pale green flame, slowly burning the humanoid bones, burning the pale red blood stains on the bones little by little.

"It's done!"

Shan Thirteen's nervous expression relaxed slightly, and at this moment he entered the second link, which was the refining mound, this step was simple, and he only needed to constantly input backbone qi into it.

Shan Thirteen's left hand absorbed the spar aura, and his right hand continued to output backbone energy, forming a balance with each other, and it lasted for three days, and finally succeeded in refining the mound.

At this time, the humanoid skeleton completely changed its appearance, the whole was only the size of a palm, and the shrunken bones were compressed between each other because of the compact squeezing, and there was no trace of gaps, and the whole was a piece of green and shining bone jade, exuding the light of jade.

"There's a smell of green life!"

Shan Thirteen is playing with the green bone jade, this is the bone mound that has been refined at a huge price, it is a little incredible!

Poof......

Shan 13 cut a palm-length slit on his left arm, stuffed the green bone jade into it, slapped it hard, and attached it to the ulna, and the ulna couldn't help but turn into a pile of bone powder.

"Quenching the mound!"

As soon as the thirteen soul fire of the mountain moved, the ice light osteitis covered the bone meal, making a crackling sound, and gradually the bone powder was like a broken bone condensation vein, forming again.

Swish......

The thirteen bones of the mountain were swallowed by the ulna without exception, and gradually a green spot appeared, and faintly, a green hazy patch was expanded within the ulna.