Breaking through required time. Complete, utter focus. It was not something one could, or should, rush. Alas, I didn’t have time.

Clearly, breaking through with enemies all over Cintre was stupid. It wasn’t something I should have considered, yet I did. And not only did I consider breaking through, I actually went through with it.

"Protect me," I ordered my demon subordinates while giving the Trickster Demon the mental command to hide me or make it seem like I was elsewhere.

Then, as if my Core decided it was time for me to advance as well, it began to expand.

The Essence stored in the Core erupted and grew, pressing firmly against its outer walls. The sound of breaking glass echoed in my ears as the Core cracked. Hairline cracks spread across the entire structure as it expanded forcefully, but they did not persist for long. The cracks were mended as Essence seeped into them, healing the Core while providing enough energy to push it further.

Essence flooded the Core as it expanded, cracked, and was repaired. That didn’t require much attention from my side, not directly at least. What I had to do was something else entirely. First, I had to control the Essence flow. Infusing too much Essence into the Core’s cracked structure would initially mend it, but it would also put too much strain on it, resulting in larger cracks as it expanded again.

To ensure the breakthrough passed smoothly, the Core’s cracks couldn’t be much larger than a hair’s breadth. Any more, and the Core might never be the same. In the worst case, it would be permanently damaged, creating a leak that would... well, it would leak Essence constantly, forcing the Chosen to absorb a certain amount of Essence every day to maintain the Core’s saturation level. Breaking a Core was possible as well, but as far as I could tell, that rarely happened.

Too much Essence was bad. That much was clear. Nobody wanted a damaged Core. That being said, infusing too little Essence into it was just as bad. Infusing too little—just enough to repair it and nothing more—would stop the advancement. The Core wouldn’t receive the Essence needed to expand further and complete the advance.

If stopped in a timely manner, it was possible to remain at the 1st Tier and repeat the process, but if the Core cracked three times and absorbed enough Essence to reach the lowest threshold of a Tier-2 Core, the breakthrough was considered complete. The Chosen would have reached the 2nd Tier, yet the breakthrough would have been the weakest possible, even if he or she had more Essence to infuse into the Core.

Hence the importance of a stable but sufficiently strong Essence flow, which required a considerable amount of effort and concentration—concentration that might falter mid-combat.

Fortunately, I was not caught up in combat. Not directly, at least. The sound of battle reverberated in my ears, and I watched Rotheart Vampires and Lesser Demons attack demihumans—both citizens and guards—as well as human Hunters, but I kept to myself. I didn’t help anyone, my focus lingering on the streams of Essence I had just formed in my Core. 𝒇𝙧𝙚𝓮𝔀𝓮𝒃𝙣𝓸𝒗𝒆𝒍.𝙘𝒐𝒎

Ten streams of Essence, each roughly the same size, came to be. So did the mind-splitting headache that tried its best to hinder a smooth breakthrough.

But I stayed focused. At least, I hoped I was focused enough as I shoved the first Essence stream into my Core. The initial cracks healed seamlessly, but the Core expanded only slowly—much slower than I expected. It didn’t expand all that much either, making me wonder if I had used too little Essence.

The remaining Essence streams fell apart as those worries gnawed at me, reforming into six streams. The cracking sound coming from my Core filled me with relief, and without wasting time to recover or get myself under control, I infused another stream.

This time, the response was much more obvious. The cracks disappeared one moment, only to reappear the next. My Core was expanding, but I focused on the cracks as they spread across its entire surface. Then they grew wider, making me curse. That was not what I had wanted to happen, yet it was happening right before my eyes.

Fortunately, the Core did not break apart or show any signs of the cracks calcifying and remaining as I infused yet another Essence stream. The cracks healed as the expansion continued, but they soon returned.

That’s too much Essence. But the cracks are larger now, so they need more Essence to heal. I cursed inwardly, changing my tactic once more. Then I continued, the chaos of combat reverberating like muffled voices in my ears.

While I couldn’t see exactly what was unfolding around me, I could sense it. My subordinates were struggling. Four of the two dozen demons were already dead. However, in their wake lay ten more crippled Lesser Demons for me to force into submission, along with several writhing masses that must have once been Vampires.

But not all was well. After revealing the Juvenile Nature Dragon form, the attention of many had shifted to me. More demons and vampires surged in my direction, and it wouldn’t be long before the remaining subdued demons fell in their wake.

I didn’t have much time to consolidate the breakthrough or spend hours adjusting the Essence flow for a perfect result. My method was raw and violent, yet it seemed to be working well enough—until something cold and eerie mingled with my Essence and flowed toward the Core’s hairline cracks.

The demonic energy gathered from forcing two dozen demons into submission had to go somewhere as the demons that owned it succumbed to my enemies. And instead of pouring out of the Core and into the surroundings, it poured inward, altering the breakthrough permanently.

But what exactly did that mean?

The answer was simple: I no longer wielded an ordinary Core.

Demonic energy fused into the 98% saturated Core, providing the very energy needed for a perfect advancement. As for what else it meant... I had no fucking idea.