Consuming friction between the fractures, the wall's rocks opened into a recess, a kind of compartment hidden in the wall. That gloomy locker contained a small cubic box sealed by a lock.

When all the tiles holding that wooden chest, locked in its place, were moved by the magic of the three spirits, it flew to Osai, the legless man. ​​

Yoichi and his companions continued to witness the scene, not knowing what was about to happen. When the chest was tightly held in the hands of the spirit of the central tombstone, the eldest of the three brothers began to speak again.

"Too many years have passed since the day of our death. So many that they're impossible to remember. My brothers and I loved this mine. It was our home, our family, our everything... aaaah," he spoke.

"Although our memory tends to fade, we remember the arrival of demons with extreme precision. From that day on, the fate began to write our end inexorably", Osai added.

"Demons of all kinds drove us miners away, devouring the most fragile and forcing the strongest to fight and shelter themselves in the caves", Asai continued. "By now, there was no one left. The three of us were the last survivors of the Blackvault Mines."

"The last survivors? You mean... had everyone else been mauled except for you?" Enatsu asked. Taking advantage of that rhetorical question, the merchant wanted to extrapolate as much information as possible from the three mysterious spirits.

They continued to speak cryptically, omitting information on purpose. Their intention was probably to bring the three travellers to reasoning, giving them small glimpses of their past life.

"Eyes as red as flames and jaws as sharp as spears. The last screams of the men who had shared this place with us for years turned into oblivion, eaten by darkness", Asai replied.

"They were like brothers to us. They were our family. Our unchanging task was to extract the Tetsuiasa, the precious material that would be given to the imperial family", Osai explained.

"The perfect alloy between iron and gold. Durable and shiny, suitable for building armour and embellishing jewellery. Of all the places in the world, our mine was the only one capable of producing such a mineral. The only one in all over Lumya."

After Ysai's words, Yoichi and Enastu looked at Shioko. From the way she looked puzzled at the storytelling spirits, she seemed to have never heard of the Tetsuiasa.

"What happened to Tetsuiasa?" Yoichi inquired, curious about what that story had to do with their looming test.

"My two younger brothers and I have always been the strongest in here. Our arms were able to lift twice our weight and, while we did not have the gift of taming demons, we were able to stand up to them. However, it was our fraternal union that killed us," Ysai explained, leaving room for the intervention of the other two spirits.

"Despite our dedication and constant efforts, the pay we received from the nobles who had owned the mine was too low. We could hardly feed our children, and our wives looked at us with outrage," Asai spoke.

Osai squeezed the small wooden trunk next to his chest. "Unlike the landowners, we knew every single corner of this cave, every hole and every crevice. As anyone else would have done in our place, we hid a small loot, enough Tetsuiasa to create a piece of equipment," he admitted.

"One of us, during our escape, convinced the other two that we would be able to recover our hidden treasure in time before we left the mine. A brother's greed prevailed over the survival instinct of the other two. And where to hide a precious loot, if not in the only left-end room in the cave?" Ysai acknowledged.

"A narrow and long room, low in minerals and of little commercial interest. We knew that none of our colleagues, nor our masters, would ever look in here," Osai remarked.

"When we reached the wall behind us, caught in the anxiety of being killed by the demons after us, we could not find our secret loot. At that point, the vaults of the room collapsed, and we were sealed in this place. Forever," Asai concluded.

After that tale, Yoichi linked the appearance of the three spirits to what had happened in the past. Asai's damaged head and missing arm, Osai's severed legs. Poor Ysai with his own head between his hands: the mine that represented everything to them, had suddenly become their grave, and the three brothers who had dedicated their lives to the extraction of the Tetsuiasa had died crushed under the weight of their regrets.

The three adventurers were speechless, knowing that that story was not over yet. Their next mission would not involve the use of their pets, and the fear of not succeeding began to flow through their veins.

"Your mission is to figure out who of the three of us caused our deaths. Who is the brother who put his family's life at risk for a loot worth a few dozen gold coins" Ysai explained again, starting to talk about the test.

"Did he really say a dozen gold coins?!" Enatsu whispered, shutting his mouth with his hand. Every time somebody talked about merchandise and money, the young merchant couldn't hold back.

"Shh! Shut up and listen!" Shioko scolded.

"Only by declaring who is the architect of our death will you be able to get out of here safely", Ysai repeated.

"Do not try to destroy the walls, nor to remove the rocks that block the door. You wouldn't do it in time and die as we did," Asai added.

"Thousands are the tamers who, like you, have accepted the mission of the three tombstones. Insects devoured their bodies, and their bones fed the limestone rocks. You only have one chance," Osai spoke.

"The three of us will stay here and watch you, but we will not say a word. When you are ready to solve the enigma of the three brothers, you will know the truth", Ysai concluded. Suddenly, the head in his hands closed its eyes.