Alan walked around the area filled with undead body parts, his focus drawn to several iron plate necklaces scattered on the ground. He picked one up and examined it closely, finding inscriptions on each plaque.

"Lumine, 0207115. Possibly the owner's name," he thought. "The date on another part indicates they've been here for hundreds of years. This place seems to have been used as a dumping ground by the empire for a long time."

"No wonder there are so many undead roaming around here," Alan thought. "Perhaps that's why it's called the ancient tomb. But, I'm curious how these corpses turned into undead."

He noticed a skeleton sitting at the edge of moss-covered rocks, with a rusty short sword beside it.

"This skeleton looks different," Alan thought. "I wonder how it ended up here."

Alan took the necklace from the skeleton and cleaned it from the moss.

"Yakoz, 26 08 2016," he said. "This must be the oldest of all the skeletons here. But the year 2016? It's the year 705 in the empire. What happened?"

"It couldn't possibly be from the future," he thought. "Perhaps they used a different calendar system."

"With the knowledge I have, no human kingdom has lasted more than 2000 years," he continued. "This sword also doesn't resemble those commonly used by the empire. It seems to come from an eastern kingdom, though it's shorter than usual."

Alan tried channeling his mana into the sword, and instantly, the rust on the sword was covered by a dense black aura.

"This sword reacts to my mana," he thought in amazement. "And it also feels light."

He swung the sword towards a large rock in front of him, embedding it in the rock. Alan pulled it out slowly, like pulling a knife through butter.

"Such a peculiar sword," Alan said. "Though its shape is unusual, it resonates with my mana. And it's stronger than these chains. But it might not last long, so I better keep it."

Alan continued his journey deeper into the cave. The air grew denser, reminding him of the difficulty breathing when he first entered the cave.

He arrived at a large monument, Alan had a feeling that the next area would be more dangerous.

"But there's no choice but to move forward," he said.

Several giant rats were fighting over wild moss. They stood 2 meters tall when upright, with sharp claws and horns, and reddish-brown fur. They turned towards Alan as he passed the monument.

Alan prepared, extending both chains down, while a thin black smoke enveloped the chains. He was ready to attack.

The rats began to squeak deafeningly, then ran towards Alan with glowing red eyes.

The chains swung fast, hitting the rats, and their squeaking stopped instantly as their bodies were split in two. Alan continued forward, facing danger after danger in the increasingly dark cave.

Hours later, he found himself in a deeper room. Suddenly, a large wolf jumped from behind him. Its fangs protruded from its large, red jaws.

Alan quickly dodged, jumping and rolling forward to avoid the wolf's attack. He realized the wolf was much stronger than the previous rats.

He swung his chains quickly, but the wolf was too fast. The chains only hit the ground, missing their target.

The wolf leaped towards him swiftly. Alan tried to dodge, but the wolf managed to attack him and injure him.

Alan felt a piercing pain as the wolf threw him against a rock wall. He felt desperate but couldn't give up.

With his last strength, he fought back against the wolf. His short sword resonated with his mana, and he managed to injure the wolf.

Blood poured as the wolf was split in two. Alan felt relieved, but his body was severely wounded.

He fell to the ground, feeling exhausted and weak. But he sensed something strange happening.

A faint light emerged from the divided body, reaching towards Alan. Slowly, black smoke blew from his wounds, his bleeding stopped, and his injuries began to heal.

Alan looked at the wolf with relief. He felt his strength increasing, and he realized he had to continue forward, no matter how many obstacles he faced.

"With this power, I can fight any danger," he thought.

Alan stepped forward, entering rooms that grew darker and more dangerous. He knew his adventure had just begun, and he was ready to face anything that challenged him in this mysterious cave.

In the midst of the darkness, Alan saw a faint light illuminating the winding corridors. He sensed the presence of something powerful and mysterious at the end of the corridor.

Suddenly, a towering stone monument appeared before him. The writing on the monument appeared ancient and was not easily read by Alan. However, he felt there was something important behind the writing.

"With this new power, I might be able to read these ancient inscriptions," Alan thought.

Using the energy he had just discovered, Alan focused on understanding the inscriptions on the stone monument. Gradually, the initially unclear letters began to make sense to him.

"This is... the Poisonous Marsh," he murmured. "It seems to be a warning about the dangers awaiting me on the fifth floor."

Alan felt the tension rising. He knew the challenges ahead would be even more difficult.

With a firm heart, Alan continued his journey through the dark corridors towards the Poisonous Marsh. He remained alert and ready to face any obstacles that might emerge.

Upon reaching the entrance to the Poisonous Marsh, he felt the air getting heavier and struggled to breathe it in.

"This won't be easy," Alan thought.

Carefully, he stepped into the Poisonous Marsh. He felt the soft, slippery ground beneath his feet, and a foul smell filled the air around him.

Suddenly, he heard a rumbling sound in the distance. He saw something large and terrifying emerge from within the marsh. It was a monstrous guardian of the Poisonous Marsh.

Alan prepared himself for the confrontation. He knew that engaging this creature would require all his strength and cunning. The beast, covered in thick mucus and with eyes that glowed with a malevolent light, seemed to be aware of Alan's presence and began to move towards him with deliberate intent.