Is that a Wisp?

"I've finally reached Tier 6." Krune smiled, sensing the changes in his body. Now, he had obtained the complete body cultivation method, getting excited. He wished to return to the God Realm immediately.

Nevertheless, he still had to find Feifei. On top of that, he had to become stronger in Tier 6 so that he could roam through the miasma and head towards other cities. This way, he'll be able to make enough preparations to ensure that Feifei would be safe when she arrived at Layer 2. 

'Now, I'll have to upgrade Hazak,' Krune thought, smiling as he saw the second Tier 6 Demon Core Fragment. After that, he commanded Hazak, "Generate enough miasma to condense a body for this once it forms into a Tier 6 Demon Core. Stop before its head forms."

Hazak nodded and began to stuff itself full with the red fishes, producing miasma once it was done. It constantly compressed the miasma until it turned into liquid, storing it in one large tub.. It continued to fill the tub with liquid miasma, busying itself in the process. 

As for Krune, he continued to develop his weight in Tier 6. Of course, he also helped Wrister and Flita break through the limit of Tier 5, causing them to shed tears of gratitude. He just thought it would be helpful to make them this strong. 

After all, he needed them to work for him until his wife was found. Since they were loyal to him, it was the best option. Besides, upgrading them didn't need any extra energy. Krune had enough to sustain all his needs. 

Four months later, Hazak had filled the tub full of liquid miasma, sighing in exhaustion as Krune dropped the Tier 6 Demon Core Fragment into it. Like a vortex had been created, all the liquid miasma gushed into the Demon Core Fragment, causing it to begin growing immediately. 

Soon, when there was a tenth of the liquid miasma left, the Tier 6 Demon Core finished forming. Immediately, flesh started to condense around it, birthing internal organs, soon resulting in a body.

The Black Demon began to grow, stopping when the miasma was emptied. Hazak then took a deep breath, trying to lift the Black Demon corpse when it was amazed at the weight. "It would have revied if I had poured a bit more liquid miasma."

Seeing Krune nod, Hazak carefully opened its mouth, biting the Black Demon, struggling to even pierce its teeth into the flesh. It was to the extent that its teeth shattered by the time it managed to tear a tiny piece of the Black Demon's skin. 

Thankfully for Hazak, it could easily recover itself using the miasma. Once it regenerated a new set of teeth, it began to tear into the Black Demon's corpse once again. During its free time, Hazak generated liquid miasma. In the rest of its time, it continued to eat the Black Demon's corpse, repeating it as it struggled a lot, howling in pain from time to time as even its jaws shattered from time to time. 

Hard!

As the pinnacle of the beings of Layer 2, and possessing a weight of 3000 kilograms in its tiny frame, the Black Demon's body was spectacularly dense. After all, it took Krune a month just to saw through the Black Demon's horn. Thus, it was apparent of the toughness a Black Demon possessed. 

There was one difference between all the demons and a Black Demon, though. Typically, every demon began to march towards a city once they were given birth. So, they didn't have enough time to develop. 

So, when they arrived at the battlefield, humans were able to kill higher-tiered demons by grouping up to a certain extent. That's how they managed to kill the demons and grow stronger. Moreover, once they began to develop in Tier 5, they no longer faced any threats.

After all, most, if not all the Red Demons that arrived at the battlefield would only weigh around 1500 kilograms. It was a sharp contrast to the Tier 5 humans that have grown in weight by killing the weaker Red Demons constantly. 

Thanks to that, they were able to kill the Red Demons, allowing more Tier 5 humans to be birthed. This happened in every tier, a reason humans were able to kill the demons in the first place, in the first generation when their bodies were the weakest. 

They started with the Demon Soldiers, pitting tens of themselves to kill one foe. And by eating the Tier 1 Essence generated from that pyrrhic war, the first generation of Tier 1 Warriors was born. After that, they slowly accumulated strength through numerous losses, killing higher-tiered demons one after another.

Eventually, they managed to produce enough Tier 5 Warriors to keep their cities stable and cause their population to boom. 

Of course, everything only happened because no demon ever grew much in its respective tier, killed before it could tap into even a tenth of its potential. Sadly, Black Demons weren't like this. 

Since the start, they never fought humans, gone against the instinct ingrained in their race. They stayed within the miasma and continued to grow stronger, eventually reaching the peak of Tier 6—3000 kilograms. 

The peak of Tier 5 was only 2000 kilograms. So, the difference of 1000 kilograms was too vast of a level to scale against. This was the reason no human was able to kill a Black Demon and attain the Tier 6 status. 

Plus, since the horn was from the Black Demon that was at the peak of Tier 6, even the corpse Hazak grew using the miasma conformed to the same, the fully grown body of a Black Demon. That was why Hazak struggled to even damage it, howling in pain whenever it broke its jaws by exerting too much strength in an effort to rip apart the Black Demon flesh. 

But as months passed, Krune was able to help out since he was growing in strength in Tier 6. Even though it still took a lot of effort, the speed of progress was at least faster now. Thanks to that, Hazak was able to eat bits and pieces of the Black Demon flesh. 

Two years after they embarked on this endeavor, Hazak's skin was finally faintly tinged with a shade of black.