As the two of them moved closer to the heart of Graydusk Forest, it became easier for them to find mutant spirit beasts.
Through one of his Heaven Eyes, Nie Tian located another group of mutant spirit beasts and determined their grades.
"None of them are at the sixth grade or higher. Li Langfeng will be able to handle them himself." With these thoughts, Nie Tian pointed out their direction to Li Langfeng, and Li Langfeng dashed off to kill them, while he stayed and formed another Wood Thriving Formation.
A hour passed...
Li Langfeng dragged the bodies of seven mutant spirit beasts back to Nie Tian's location. Looking somewhat tired, he said, "Two of them are at the fifth grade, the rest are at the fourth grade."
He had also cut off these mutant spirit beasts' heads in the same manner as before.
Nie Tian nodded and signaled for him to leave the corpses in the spell formation, so he could absorb their flesh power with Life Drain.
However, as soon as he launched Life Drain, he discovered something different. "Hmm?!"
The speed at which he could absorb flesh power from these mutant spirit beasts had become twice as fast as before.
In just a couple of minutes, he completely drained a fifth grade mutant spirit beast of its flesh power.
Watching the fifth grade mutant spirit beast being drained dry within such a short time, Li Langfeng was also surprised.
"Does it have something to do with the recent refinement of my heart?" Nie Tian thought to himself. It seemed to be the only explanation for such a pleasant change.
His eyes lit up. "I've only finished one third of the refinement of my heart, and the efficiency of my Life Drain has doubled..."
However, he didn't dwell on it, but continued to absorb flesh power from the other mutant spirit beasts, and conducted a second round of refinement of his heart with Heavenly Wood Heal and the Wood Thriving Formation.
Several days passed, and when he was finished, the refinement of his heart was two-thirds complete.
As he opened his eyes, he found, to his surprise, that about ten more dead mutant spirit beasts were piled up right outside his spell formation, three of which seemed to be at the fifth grade.
Smiling brightly, Li Langfeng said, "These mutant spirit beasts passed by during the past few days, so I killed them all for you."
Nie Tian nodded with an impressed look in his eyes, and said, "We need to switch to another location. I've already absorbed all of the wood power in the vicinity."
"Umm…" Li Langfeng seemed somewhat hesitant and shamefaced. "If we go any further, we might encounter sixth grade mutant spirit beasts. As you know, sixth grade mutant spirit beasts are as strong as Profound realm Qi warriors. I'm afraid that I won't be able to kill them by myself."
"That's alright." With these words, Nie Tian took his time to summon the Bone Blood Demon from within his ring of holding. Then, he cut his palm and dripped his blood on its exposed, smooth bones.
The Bone Blood Demon's flame of life was instantly ignited. Uncanny, grayish-green light flickered in the depths of its beady eyes. In the next moment, it jerked its head towards the few mutant spirit beasts Li Langfeng had recently slaughtered.
Apparently, it had sensed the rich bloody aura, which it could use to strengthen itself, within them.
With a thought, Nie Tian stopped the Bone Blood Demon from acting on its thought. Instead, he commanded it to carry all the dead mutant spirit beasts as they marched deeper into Graydusk Forest.
After marching a few dozen kilometers, he stopped to establish a new Wood Thriving Formation, and commanded the Bone Blood Demon to place all of the dead mutant spirit beasts inside the spell formation.
He once again launched Life Drain.
This time, he was completely convinced that the refinement of his heart, which he had achieved with Heavenly Wood Heal, had a great enhancing effect on the efficiency of Life Drain.
That was because after his second round of heart refinement, the speed at which he could channel flesh power into himself had doubled again.
"I can't believe that the refinement of my body can actually strengthen my bloodline talent! This is brilliant!"
After draining the mutant spirit beasts of their flesh power, he left the Bone Blood Demon and Li Langfeng outside his Wood Thriving Formation, and told them to kill any mutant spirit beasts that strolled into this area.
Afterwards, he focused on the last refinement of his heart.
This time, the refinement process lasted ten days, which was longer than the two times before.
As he consumed all of the newly-acquired flesh power, and the lush vegetation around him withered and died, he finally finished the last step of the refinement of his heart.
During the process, he saw every strand of tissue in his heart being severed and reattached, and as they did, his heart ballooned up and shrank down from time to time.
Now, as the refinement of his heart was finally complete, the last obstacle in his path to his next breakthrough had been shattered.
The vortexes of spiritual power in his spiritual sea suddenly started to become active.
Nie Tian was surprised to realize that he could try to break through into the late Greater Heaven stage right away!
Without the slightest hesitation, he summoned spirit jades and spiritual materials of different attributes from within his ring of holding, which rapidly piled up in front of him.
Only then did it occur to him to scan his surroundings. He discovered that the Wood Thriving Formation had already lost its effect, since it had drained all of the wood power in the vicinity.
The Bone Blood Demon had also fallen into a deep slumber.
Placed next to it were a dozen dead mutant spirit beasts, some of which seemed to be at the fifth grade.
It was just that they had apparently been drained of their blood by the Bone Blood Demon. Even so, there were still copious amounts of flesh power within their bones, internal organs, and meridians.
However, it was beyond the Bone Blood Demon's ability to absorb flesh power from those parts with the Blood Refining Incantation.
"Nie Tian, you're finally awake," Li Langfeng said, smiling. "I didn't do much this time. It was your puppet that killed all these mutant spirit beasts for you."
Nie Tian nodded. "We don't need to go any further for now. I'm ready to make my breakthrough."
With these words, he walked to the Bone Blood Demon and once again ignited its flame of life with his blood.
As the Bone Blood Demon's eyes started to flicker with grayish-green light again, he sat back down.
Since he wouldn't need much wood power to make his breakthrough, he didn't move to a new location or establish a new Wood Thriving Formation.
Furthermore, if he moved closer towards the heart of the Graydusk Forest, it would be hard to predict what kind of powerful mutant spirit beasts they might encounter.
To be safe, he decided to stay away from unnecessary risks when he made his breakthrough to the late Greater Heaven stage.
Just as he picked up a piece of spirit jade to channel its immense spiritual power, a sharp sound came from the Sound Stone in his cuff.
This Sound Stone had been given to him by Dong Baijie, and allowed him, Dong Baijie, and Dong Li to communicate over rather long distances.
However, for some reason, he had never received any messages from Dong Baijie this whole time. It had always been Dong Li who had contacted him.
But it turned out to be Dong Baijie this time.
"What's the matter?" Nie Tian asked.
"You're finally responding!" Dong Baijie sounded anxious. "Dong Li and I have been looking for you for quite some time. We've sent you many messages, but you never responded!"
"I was cultivating," Nie Tian said.
Even the noise of the Bone Blood Demon slaughtering nearby mutant spirit beasts had failed to awaken him, not to mention the chirping sounds of the Sound Stone.
"The outsiders are here, and they're coming at us with overwhelming force!" Dong Baijie sounded very nervous. "I'm not in the Void Illusion Mountain Range, but according to the word I received, our defensive forces are now in a very unfavorable situation! Ten seventh grade outsider experts have descended through those spatial rifts!
"Our alliance suffered setback after setback. Now they've almost been forced out of the Void Illusion Mountain Range!
"Many powerful experts have sensed the seriousness of the matter, and thus demanded that every single Soul realm expert in the Domain of the Falling Stars stop whatever they're doing and come to the Void Illusion Mountain Range immediately!
"That puppet of yours is also on the list.
"People are now searching for you. They want you take it to the Void Illusion Mountain Range and join the battle as soon as possible.
"But the decision is yours, Nie Tian. If you don't want to join the battle, just stay stay out of sight. I'll pretend that I've never gotten in contact with you."
Dong Baijie didn't ask where Nie Tian was, or what Nie Tian was doing. He only quickly explained the situation to him and let him decide what to do.
After sending these words, he took the initiative to end their conversation, as if he were afraid that someone would notice.
Various expressions flashed across Nie Tian's face as he put his Sound Stone away.
"What happened, Nie Tian?" Li Langfeng asked curiously.
As a lone wolf, Li Langfeng had no friends. Therefore, he didn't have any means of receiving news from the outside world.
Nie Tian sighed. "The outsiders are finally here."
Li Langfeng gasped with astonishment. "How's the situation?"
Nie Tian's eyebrows knitted as he said, "Our alliance is in a very bad place. Apparently, ten powerful seventh grade outsiders have come to the Void Illusion Mountain Range. Our Soul realm experts are at a noticeable disadvantage in the battle against them. It seems that the Void Illusion Mountain Range will fall into the outsiders' hands soon."
Li Langfeng's eyes were filled with fear as he said, "Once the Void Illusion Mountain Range falls, the outsiders will be able to swarm into Shatter City, Ash City, and the Land of the Abandoned without meeting any obstacles. From there, they'd be able to teleport to the other realms. Then, the entire Domain of the Falling Stars will be soon filled with outsiders. If it really comes to that, the people of the Domain of the Falling Stars will be plunged into an abyss of misery."
"Some Soul realm experts have ended their secluded cultivation and are now rushing to the Void Illusion Mountain Range." After a short pause, Nie Tian added, "They want me to join the battle as well."
Upon hearing these words, Li Langfeng instantly laid his eyes on the slumbering Bone Blood Demon. Frowning slightly, he asked, "So what do you think?"
After another pause, Nie Tian snorted and said with a stern face, "Whatever happens, I need to enter the late Greater Heaven stage first!"
With these words, he once again awakened the Bone Blood Demon with enough blood to keep it active for two weeks.
He was afraid that the Void Illusion Mountain Range would fall shortly, and that outsiders would roam into this area before he was finished.
Afterwards, he commanded the Bone Blood Demon to take him and Li Langfeng to a place far from Graydusk Forest, where he established a Wood Thriving Formation and focused on his breakthrough into the late Greater Heaven stage with spirit jades and all sorts of spiritual materials.
"I hope those people can hold on for a bit longer," Nie Tian thought to himself.