"The night has come. If it is true that with darkness, wild demons gain strength, it is not advisable to stand still among these trees," Yoichi continued. "I doubt that the Yoroichi is the only inhabitant of this forest", he added, beginning to look around.

Enatsu and Shioko approached him, looking up at the mountain, recognising the truthfulness of their companion's words. The entrance to the notorious Blackvault Mines had been unlocked. ​​

The black mud had managed to penetrate the narrow fractures of the granite rock of that cliff, enveloping the recess in the wall and making it even darker compared to its normal condition.

That natural door was the only entrance and the only exit of the dungeon. Stepping forward, the young tamer took a deep breath.

Before his companions could add anything else, Yoichi slipped his hand into his leather pouch, pulling out the keikemon. He squeezed the fruit given by Kuniaki in one hand while the other pulled the dagger from the back of his belt.

Something tells me that not all demons in this dungeon have been infected with the dark substance. If we really have to beat them and their boss, little extra XP points would suit Kenji, he thought.

Sinking the blade into the centre of the cobalt blue citrus, Yoichi divided it into two identical halves. Like an orange, the pulp exuded a sugary liquid with a delightful smell.

"Swallow it with all the peel", Shioko suggested, speaking from the rear.

Yoichi silently accepted the advice and approached half of the keikemon at Kenji's mouth: the little dragon, having never seen such an object, sniffed it carefully.

A slight grimace appeared on its face and its red eyes narrowed due to the acrid smell of the magic fruit peel. "Eat it, buddy. See? Do as I do," Yoichi whispered, sticking his half in his mouth and beginning to chew it.

Drops of light blue fluid poured from the young tamer's lips as he continued to chew the large piece of the keikemon. The sour taste of its peel was perfectly compensated by the sweetness of its pulp, making it a fresh and delicious snack.

Sharing that pleasant feeling with its tamer, Kenji bit its half, swallowing it voraciously. Repeating the operation, the little dragon ate the magic fruit, activating its power.

"I can't feel any difference. Is that normal?" Yoichi inquired, imagining that Shioko had already eaten one in the past.

"The magical power of the keikemon will be triggered every time you finish a fight, for the next 24 hours. How did you get it?" Shioko asked, intrigued.

"The shaman gave it t..." – Yoichi's words were suddenly interrupted by strong vibrations of the ground. The three adventurers promptly turned to the spot where the big Yoroichi had been buried.

In that area, the ground under the layer of mud was rising and falling, as if something was trying to open a gap from the depths.

"Oh, fuck... we have to hurry! We can't rechallenge it at night... other demons would come to its rescue", the archer exclaimed, getting even closer to the entrance of the cave.

Without further hesitation, she and Nobu entered, followed by Yoichi and Kenji. Enatsu, who as usual closed the line, discovered with great amazement that the bodies of his companions and their demons had disappeared into nothingness soon after crossing that threshold.

"Okay... I had hoped that the dungeon would no longer be active, but... apparently... it is" *gulp* - swallowing empty, the merchant took courage and entered the cave with Rokuro, his Moruba.

As soon as his foot overcame the natural boundary formed by the rock in contrast to the muddy terrain, he felt a strange sensation spreading throughout his body.

It was as if someone had pulled a blanket away from him, exposing his body at night: a feeling of sudden cold turned into a thrill that lasted a single moment.

When Enatsu crossed the threshold, Yoichi and Shioko were stationary a few meters away. In front of them, a narrow rocky corridor was dimly lit by Nobu's tail.

An old wooden sign was set in the ground on the left, giving that place an even more macabre look. 'Blackvault Mines' it read, with a trail of hand-shaped blood next to the letter T.

Just below the wooden rod that held the inscription, human bones were scattered here and there. Every single skull, rib and femur had been deprived of its flesh, stripped to the bone.

"Oh, fuck!" Enatsu trembled, taking a step back and touching the opposite wall with his shoulders. Without paying attention, he dirt the back of the armour with the sticky mud. "Shit!"

"Does every dungeon have a sign like that?" Yoichi inquired, looking at Shioko and the rest of the tunnel out of the corner of his eye.

"All dungeons registered by the Lumya Tamers Association, yes. As you already know, each place can potentially become a dungeon, so there is a need to count them. The Blackvault Mines have been a dungeon for a long time; that's why the sign is in those conditions," Shioko explained, beginning to walk forward with confidence.

Yoichi merely stored that information without responding. Inside the tunnel, the floor rocks surfaced above the mud, which could not accumulate on them.

That strange dark substance seemed to come from the other side of the tunnel and completely soiled the area. Shioko approached a wall and swiped a finger on it, removing a fragment of that strange material.

Approaching it at the tip of her nose, she smelled it and then squeezed it between her fingers, assessing its texture. The red-haired tamer seemed to follow tracks like a hunter chasing his prey.

"The temperature inside the cave is lower than the outside. However, this strange sludge is warmer than the one beyond the exit," she commented, specifying that detail.

Yoichi approached her, resting the tip of his index finger on the wall, dirty with mud. "That can only mean one thing. The 'source' that generates the mud is nearby; there is no doubt", he added, drawing conclusions.

The rock tunnel was about two meters wide, and the ceiling height was the same size. Recalling the thick saliva between the jaws of the Hebigure, black mud flowed from the ceiling, forming small stinking puddles on the rocky ground.