The physical upgrade of the upper realm was truly absurd. To harvest a core, he would execute a series of precise, practised motions: with a swift wave of his sword, he cleanly cut open the thick hide on the monsters’ backs.

The cores were located in a peculiar anatomical position, nested snugly right next to the upper segment of their spines. It was an unusual, highly specific location for a mana centre, but biologically, it served an ingenious purpose.

By being positioned directly against the spine, the core could supplement the monsters’ physical bodies with an immediate, uninterrupted flow of spirit power, routing it directly to their most vital nerve centres and motor pathways. This direct injection method entirely eliminated the need for the creatures to channel spirit power through a complex network of internal meridians.

Consequently, this unique anatomy greatly lowered the total amount of spirit power the monsters needed to expend to perform high-level physical feats, which in turn allowed the cores to store massive amounts of excess spirit power over time, condensing the energy into a highly concentrated, dense form.

Working with ruthless efficiency, William systematically filled an entire storage ring to the brim with these glowing, condensed spheres. Once his inventory was full, he turned on his heel and headed straight back to the hidden location of his guild masters.

If it had taken him several gruelling hours of cautious scouting to reach the mine earlier, it took him less than twenty minutes to arrive back at their camp. Most of that brief transit time wasn’t spent running, but rather navigating around the massive, incoming waves of shadow monsters that were still flooding toward the distant fire from the far reaches of the zone.

"Wow! You really do know how to find a way to grow your strength, even in a desolate place like this!"

The very moment William’s silhouette suddenly flashed into view close to their camp, the Fox Guild masters all got violently startled. Because of his incredible, ghostly speed, they initially mistook him for an approaching enemy, a rogue entity that wasn’t a mindless shadow monster.

Their defensive response was instantaneous and swift; weapons were drawn in a heartbeat, but they strictly refrained from using their spirit powers, having thoroughly learned a brutal lesson from what had happened to their unfortunate mates just a short while ago.

However, when the figure blurred to a halt, and William stood calmly in front of them, their high guard instantly dropped. Their tense vigilance was immediately replaced by deep, unbridled curiosity. Fang stepped forward first, his eyes narrowing as he closely examined the profound, visible changes in William’s physical stature and posture.

"You managed to completely change your body..." Fang murmured, looking up at him in awe before adding, "Is this transformation something unique to you, or is it..."

"You all are going to experience that right now," William said, cutting off the need to explain a mountain of complex theories.

Without wasting another moment, William simply touched the surface of his storage ring and released the contents, taking out a massive pile of the cores he had just gathered. Everyone’s eyes were instantly magnetised by the glistening small balls. Each core was roughly the size of a tennis ball, sporting a dark green, textured outer surface with a mesmerising, shimmering green light pulsing deep inside its core.

"These..." Ro was the first one to break the silence and move forward. She reached down, gently picking up one of the glowing spheres and looking at it with a reverence that suggested she was holding the most priceless treasure in existence. "These are the cores that turned you into this?"

"Just drop a single drop of your blood over one," William instructed, giving them the exact, correct method for spirit masters of the upper realm to safely ingest raw cores.

"The moment your blood makes contact, the core will dissolve automatically and begin to enhance your physical bodies from the inside out. I want everyone to take one core each, then immediately sit down and try to sense the ambient spirit power of this upper realm. It’s incredibly scarce and thin here, I know, but at least the core’s energy will allow your bodies to begin adapting to this harsh new environment..."

"Wow! Give me one right now, then!" Sara laughed excitedly, stepping forward to grab her share.

Meanwhile, Anjie had already followed William’s instructions. She dropped her blood onto a core, watched it melt into a liquid mist, and absorbed it. As the energy flooded her system, she looked up at William, her eyes wide with a mix of awe and concern as she asked:

"What about the others? This pile is impressive, but these won’t suffice to cover even one-fourth of our total masters... This... oh my god, this is amazing! I can literally feel my body changing, becoming so much stronger..."

In the middle of her sentence, she lost her train of thought, completely unable to contain her sheer shock or act as cool and collected as she always did.

The profound, structural changes she felt rippling through her muscles and bones were nothing like anything she had ever experienced in her entire life of cultivation. Seeing her stunned expression brought a big, satisfied smile to William’s face.

"Don’t get so excited just yet, and whatever you do, do not use your spirit powers," he laughed lightly, offering a stern but warm warning. "As for the rest of you who won’t get a core from this batch, stay here and maintain a low profile. I will head back out immediately and keep gathering more cores for everyone until every single master is taken care of..."

"Are we just going to do absolutely nothing while you do all the heavy lifting?" Berry stepped up, her voice carrying a newfound layer of confidence due to the subtle growth she could already feel stirring inside her own body.

To her, the entire situation felt weirdly, comfortingly familiar. Looking at William now brought her back to the early days in the lower realm when she had first met him