Leveling Endlessly with the Strongest System

『Ding! Congratulation. You have killed 300 Children of Nightmare』

『Obtained 3 thousand units of dark energy.』

As Roy read the words that scrolled across his screen, his heart swelled with joy. He had earned 3 thousand units of dark energy, a reward well-deserved for his hard-fought battles against the insidious denizens of this dark and twisted realm. This much could be converted into 300 units of mental energy.

Previously, he didn't understand its value, but after the talk with the Obsidian Overlord in the World of Nightmare, he realized how valuable it was.

Mental energy was another name for the Power of the Sun and Moon.

It could be used to wipe out the consciousness of a power with a weak soul!

He couldn't use it as he was yet to open his sea of consciousness. But he already had a method to open it. It was mentioned in the secret tome.

『Earned a low-level resistance against the pull of Nightmare』

The notification went on to inform him that he had earned a low-level resistance against the pull of Nightmare, a power that would no doubt serve him well in the battles against Nightmarish creatures.

Delilah peered curiously at the object in Roy's hand. "What's that thing?" she asked.

Roy sighed, looking down at the mystical tome.

"Just like you, I also fell victim to the venom of the black sunflowers," he said. "I was trapped in an endless expanse of darkness. I tried to escape it but failed. When I was about to give up, a supreme being calling himself the King of the Void came to my rescue."

Delilah leaned in, her interest piqued. "The King of the Void?" she repeated. "Who is that?"

Rou shook his head. "I don't know." he admitted that he knew nothing about his savior. So far, the only thing he knew about the Obsidian Overlord was his title, rank among the kings of the void, the name of the realm he ruled, and his objective, which was the domination of the Ashen Land. "But he gave me this item. It records the method to cultivate an energy more powerful than aura and mana."

Delilah's eyes widened to the size of saucers. "More powerful than aura and mana?" she echoed. "That's incredible. Can I see it?"

Roy handed the ancient book over to Delilah, cautioning her that learning its secrets would be challenging. "Sure. But you won't be able to learn it. Your soul isn't strong enough. And don't try to force it, or you will experience nausea," he warned.

"Surely, it can't be that bad." Delilah eagerly took the tome, her eyes scanning the pages with fascination. She was determined to learn its secrets, but her excitement was short-lived. After reading the first of its several pages, she sighed in disappointment. "It's too complex," she said, her tone laced with frustration.

Roy understood her disappointment all too well. When he had first encountered the mystical tome, he had been equally clueless about its contents. It was only after using his information-gauging skill that he realized its secrets could only be unlocked by someone with a unique-rank soul, and only a young man below the age of 20 could learn it. Anyone older than that lacked the ability to unlock their sea of consciousness. Delilah was already 23 years old. She couldn't learn it even if she had a strong soul. He didn't want to make her sad. Thus, he didn't tell her the cold truth.

Roy had already strengthened his own soul multiple times in the past, but at the time, he had believed that the only benefit of upgrading his soul was gaining an additional soul slot for learning soul skills. His subspace and mana shield skills were a testament to his soul's strength and versatility.

However, recent events had made him realize that possessing a strong soul was necessary for mastering the ancient tome and becoming a soul master. It was a completely different system of power than the ones he possessed.

"Are you going to return it?" Roy asked.

Delilah replied, "Yes."

She carefully placed the ancient tome back into Roy's outstretched hands, making a solemn vow to never again succumb to its alluring pages. The mystical words inscribed within possessed a wonderful power that would alter their very language depending on the reader's identity, but they were also cursed by an otherworldly enchantment that made them incomprehensible to any who lacked a strong will and soul.

Roy stored the book in his spatial ring before looking in the distance. As he scanned the horizon, he felt an electrifying sensation surging through his veins. It was as if the air itself was pulsing with raw, untamed energy. He couldn't quite pinpoint where it was coming from, but he knew that it was close.

He focused on what he was sensing, trying to discern the source of the fluctuations. They varied in intensity, some as potent as the energy signature of a level 10 monster, while others were fainter yet no less intriguing. There were hundreds of them, and he knew that only one place could have so many monsters - a dungeon.

"Are we really doing this?" Delilah asked, a hint of exhaustion in her voice.

Roy met her gaze with a firm nod. "Absolutely. The dungeon is just a stone's throw away from here."

He sprinted in the direction where the energy fluctuations were originating from. Delilah was hot on his heels, matching his every step.

"Found it!"

It wasn't long before Roy spotted the entrance to the goblin grotto. It was hidden within a dense field of thorns. It would have been impossible for an ordinary adventurer to spot, but he was no ordinary man. Roy's mutated eyes allowed him to see through obstacles and look directly at the entrance of the dungeon.

It was shaped like an altar, and it emitted various energy signals.

Roy shared his findings with Delilah. They approached the thorny field with determined expressions on their faces.

As they drew near, the thorns seemed to writhe with anticipation, sensing fresh prey.

Whoosh!

Without warning, the vines lunged forward, attacking the two intruders with a ferocity that was both startling and terrifying.

"I knew it wasn't going to be easy," Delilah said as she quickly activated her special ability, conjuring several shimmering daggers and throwing them toward the approaching vines.

The daggers sailed through the air like a fish in water and sliced through the vines with surgical precision.

『Ding! Congratulation. Your subordinate "Delilah" has killed 20 low-level venomous vines.』

『She has gained 2000 EXP!』

Roy, meanwhile, unleashed torrents of fire magic from his palm. The dozens of vines that dared to attack him were banished from existence before they reached anywhere near him, but their death didn't mean the end of the flames. They continued to grow and expand, engulfing the thorny field in flames and reducing all the reddish-black vines to charred ashes.

In but an instant, a field of thorny vines as big as a football stadium was reduced to nothing but smoke and ashes!

『Ding! Congratulation. You have killed 3000 venomous vines!』

『As a result, you have earned a huge amount of EXP!』

Roy waved his hand, and the raging wildfire was out. The smoke cleared up, and then he and Delilah strode towards the ancient altar, the centerpiece of the thorny field. It was the only thing that remained unharmed, showcasing Roy's insane control over his fire.

"Is this it?" Delilah asked as she looked at Roy.

Roy nodded at her, "It's the entrance of the dungeon. But it's closed. We need to feed it with energy to open it."

"Got it," Delilah said as she placed her hands on the altar. Inner energy surged out of her hands and went into the altar. As she fed the altar her energy, the altar revealed a malevolent red glow.

She gasped in surprise as it started sucking her aura rapidly. Before she knew it, her inner world was sucked dry of aura by the altar. But in return, the altar materialized a shimmering portal before them.

Delilah tried to go through it but failed.

After he saw her crashing into it, Roy couldn't help but smile at her silliness. But he quickly shut his mouth when she glared at him like a fierce tiger.

"What's with this stupid thing? It summoned a portal, which is not useable!" Delilah said as she slapped the altar in frustration.

"It is yet to be fully activated," Roy told her.

Without hesitation, Roy fed the altar his precious pure mana. The malevolent light in the goblin-shaped altar brightened, and at the same time, the portal began to glow with an otherworldly light.

"Now it can be used," Roy said as he jumped into it.

Delilah followed his example, disappearing into the vortex of blue and gold.

『You have entered the low-level dungeon "Goblin Grotto"』

The notification landed in Roy's mind as he landed in a cave. He had finally arrived at the Goblin Grotto, a place hiding untold wonders and unspeakable horrors!