Is that a Wisp?

The group of demons then crashed into an island, dying in the process as their Demon Cores had been stolen. They were then ganged up by the Monster Geckos, tied up before being dragged by a team that carried them into a secret tunnel nearby, eventually dropping the bodies at a certain chamber. 

All the bodies dropped here had lost their Demon Cores, the only injury on their body. It was apparent that all of them had been killed by Hazak. 

The massive cavern was a bait to lure in as many demons as possible. No matter what, the Monster Geckos living in the place were tremendously weak. Even the Monster Gecko King was nothing but a mere Tier 2 being in terms of strength. 

Considering how even the weakest demon that explored the labyrinth was a Green Demon, having strength at Tier 3, they were just small fry. But of course, Feifei had planned this specific place to be the bait that would give her as many demon corpses as possible. 

And by corpses, she put a lot of focus on the corpses of the Red Demons. Thanks to Hazak hunting them, Feifei had already absorbed the essence from more than 10 Red Demons, turning into one herself. Using that, her growth speed increased further as she was now growing like a Red Demon. 

Fortunately, as the essence in her was more concentrated than a typical Red Demon, her growth speed was even faster. 

Hazak had reached the peak of Tier 6 now, turning into a powerhouse that was also able to accumulate Spiritual Energy, even though the quantity was insignificant. Then again, as it hunted the demons entering the cavern, it was also cultivating during its attacks.

But even Hazak knew that it was almost useless. After all, the Black Demons had cultivated for many centuries to obtain a basic level of power from Spiritual Energy. It was impossible for it to grow stronger quickly. 

Sadly, it had no other choice, having already reached the peak of Tier 6. Moreover, having been privy to Feifei's plan, even though Hazak didn't like her goal, it understood that her choice was pretty realistic. Or, to be more exact, Feifei was looking over the horizon, having grander plans. So, it could only grit its teeth and follow everything.

Having turned into a Red Demon, Feifei accompanied Zamuria, motioning her towards a certain chamber. "This is where I'm refining the essence of the demons."

One of the Monster Gecko Kings at the place arrived with a box, revealing the contents, showing three glowing gems within. Feifei took one of them, telling her, "This is Green Demon Essence that's been refined over ten times."

By refining, she meant causing a bone tree to absorb a Green Demon's blood while it was alive. Once it grew to the limit as a result and produced a massive fruit, another Green Demon would consume the fruit.

While it evolved thanks to the fruit, its body would be attached to the bone tree after being injured a bit. The bone tree would completely absorb its body while wilting, producing a Blood Essence Crystal in the end. 

This was a single round of refinement. The subsequent rounds consisted of feeding this Blood Essence Crystal to another Green Demon and repeating the above process, concluding the second refinement.

All in all, the process used in the second refinement was mimicked as many times as necessary until only their purest essence was condensed into the resulting Blood Essence Crystal. 

Naturally, Feifei had erected a farm to do that. There were ten such caverns in total, with each cavern dedicated to one refinement process. Like a factory line, Blood Essence Crystals were shipped from one cavern to another.

And now, three Tier 3 Blood Essence Crystals have been created. Feifei took one of them, inspecting them to see that they were barely passable. She then handed it over to Zamuria, saying, "This is a concentrated Green Demon Blood Essence Crystal that I have refined over 10 times. The quality isn't on par with what I have in mind, but this can be used."

"What does this do?" Zamuria asked, gazing at the Tier 3 Blood Essence Crystal, wondering its use. 

"Once you ingest it, you'll obtain the abilities of a Green Demon," Feifei replied, shocking Zamuria. "And by that, I mean their ability to absorb miasma and grow, heal, and so on. Of course, this isn't permanent. You'll only be able to do so for an hour at most. Also, the side effects, once its effect vanishes, are tremendous. I consumed one before, and I was unable to move for an entire day."

Feifei then pointed at Zamuria as she continued, "Since you're a lot stronger than me, the side effect you'll face should be a lot less. I have also prepared a Water Essence to heal all your injuries when the side effects appear."

"Why don't you try one?" 

"Hmm..." Zamuria wondered for a bit before smiling, interested in what Feifei had prepared for her. She then ingested the Blood Essence Crystal, coughing blood immediately as it was like she had eaten poison. Her body trembled as veins popped on her body at times. 

Feifei hurriedly fed her a concentrated Water Essence that she had condensed using her Energy Sink. 

Zamuria was able to endure after that, sitting cross-legged as she could feel the damage to her body reducing while the Water Essence healed her completely. After some time, she no longer felt any damage, opening her eyes as she could feel something different about her. 

Upon seeing the scene, Feifei gave her a bottle containing liquid miasma. Nodding, Zamuria took it, hesitantly taking a sip before her eyes lit up. She then gulped the entirety of the contents, smirking as she relaxed. "It has quite the good taste."

"How are the effects?" Feifei asked.

"Hmm..." Zamuria closed her eyes, sensing the changes in her body, "It's not anything substantial, but I am able to feel an increase in my body's weight. This is incredible, Feifei."

"Thank you," Feifei laughed as she replied. "Once your body adapts to consuming these Blood Essence Crystals, the effect would be greater.. I'll also refine them further to increase their potency and reduce the side effects."