Gravis sat in his cave and consumed the first Bone-Pill. Compared to his time when he had tempered his skin, he didn't do any additional training while consuming the pills. There were multiple reasons for that.

First of all, back then, he had tried to cut the consumption of Skin-Pills by one pill, since he had seriously lacked money. The other reason was that it was quite hard to temper bones with training. Theoretically, he could punch and kick the cave walls to temper the bones in his limbs, but what about the ones in his torso and head?

Instead, he stayed in the cave and consumed one pill every few hours. He felt his bones slowly growing more durable, and every increase only fueled his hunger for power. This time was different from when he had tempered his skin.

Over the last three months, he had grown used to his isolation, and his new short-term goal was getting back to his family in his homeworld. If he came back to his homeworld, he would no longer feel isolated and alone.

He would have his father, his mother, Orpheus, and potentially other family members. Gravis may be alone in the lower world, but not in his homeworld. It might look dark and isolated here, but he only had to get through this, and everything would resolve itself. He only needed to break through the firmament of the lower world to return.

Greed and motivation drove Gravis to continue tempering his bones. Every increase in strength brought him closer to his goal.

Day turned to night, and night turned to day again. After a full 28 hours, Gravis had finished tempering his bones. He felt their vitality and their incredible hardness. He was sure that he would not be able to break his bones, no matter how hard he tried.

Bones were, by nature, harder than skin, and this also translated into tempered bones and tempered skin. Gravis' skin was incredibly challenging to break already, but his bones were multiple times harder. Over were the times, where he would have to deal with a broken shoulder in a fight. Because, seriously, it was always the shoulder that broke.

A medium-grade demonic beast may break his skin and sever his muscles, but it would have significant difficulties in breaking the bones. As long as the limb was not severed, Gravis could regenerate.

Gravis smiled in happiness. He had realized that his increase in strength was not worthless like he had thought back when he tempered his skin. With every increase in power, he came closer to his goal in fighting Heaven and, more importantly, he came closer to returning to his family.

He no longer feared the isolation because he had a goal in mind. It might still hurt in the future to deny a friend his deserved friendship, but he could deal with it. With enough willpower, he could get through all this and reach his goal.

Gravis smirked a little. "Forneus said that when we tempered our skins and bones, some of our muscles latent potential would release itself. Our body would no longer keep a "limiter" to not damage itself. Every part of my body, except my muscles, is tempered, and my muscles can't hurt me anymore, no matter how hard they try. Let's see…"

Gravis stood up, reared back, and punched with his full power at the cave wall. The cliff trembled, and he created a hole in the wall. "Just like I thought. I've had tempered organs and blood for so long that the true natural power of my muscles already rivals others' tempered muscles," Gravis smirked to himself.

This was the reason why he wanted to temper his bones this badly. If his bones only increased his survivability, it would not help much in fighting middle-grade demonic beasts. He might survive a hit or two, but he would still have huge issues in actually hurting them.

With tempered bones, he finally had a framework that could use the full power of his muscles. His skin would not break by the muscles' pressure. His bones would not crack by the muscles' power. His organs would not get squished by the muscles' movement, and his blood was able to provide all the nutrients the muscles needed to go wild.

Now, with tempered bones and muscles that rivaled the power of other people's tempered muscles, Gravis basically counted as someone with a fully tempered body. Together with his Will-Aura, Elemental Synchronicity, and his incredible battle experience, Gravis was sure that he was the strongest cultivator in the Body Tempering Realm in this lower world.

Finally, his incredible foundation was showing its effect. Finally, he was powerful enough to not be constrained. There was nearly no one in the Energy Gathering Realm in this outer continent. When he tempered his muscles in the Lightning Guild, he would be able to break through to the Energy Gathering Realm immediately.

The biggest issue of breaking into the Energy Gathering Realm was feeling the Energy in the air. Forneus had taken out two stones with no Energy, and lots of Energy to prematurely destroy this bottleneck of the Research Assistants.

The Energy Gathering Realm no longer needed treasures or medical pills to progress. Of course, those things could accelerate the progress of cultivation, but it was no longer a necessity like it was in the Body Tempering Realm. Gravis only had to find a good place with lots of lightning and absorb it. That would already increase his strength by a lot.

After so many hardships and so many issues with money, Gravis finally saw a clear, unobstructed path forward.

"Hehehe," Gravis slightly laughed. "Ahahahaha-"

RUUUUUUM!

While Gravis was madly laughing in glee, the cliff crumbled above him and buried him. His punch was maybe a little too strong.

After some seconds, the front of the cliff blasted open, and Gravis stuck his head out. "Phew, I just entered the Bone Tempering Realm, and I already encountered a situation that would have killed me earlier." Gravis looked into the sky. "Maybe, I shouldn't grow too arrogant," he said to himself.

Gravis quickly dug himself out, cleaned his clothes, and started running along the cliff. His speed was, at least, three times faster than before. Gravis enjoyed the wind blowing in his face, and he felt like he could fly if he just jumped.

He quickly found the place from two days ago, saw the cut off pieces from the cliff, and he knew that he was back in the spider's territory. Gravis smirked and bolted into the forest.

Low-grade demonic beasts could be hunted by a group of people with tempered skin, or by a single individual with tempered muscles.

Middle-grade demonic beasts could be hunted by a group of people with tempered muscles, or by a single individual with a fully tempered body.

When Gravis first fought the spider, he was a stronger person in the Tempered Skin Realm. Now, he had basically skipped the Tempered Muscles Realm and already counted as someone with a fully tempered body. His strength was incomparable to before.

"I'm going to tear you to pieces!"