Purity

The quality of the mana contained within the core, which determines the resulting purity of items crafted using it. The more skills the denizen of the underworld possed in life, the higher the purity of the ensuing core. The higher the purity, the higher the chance of crafted items manifesting effects influenced by the original skills. If consumed, any magical items created will lose some purity in the process. 

Charge

The volume of mana remaining within a core. Once depleted, it will disintegrate. Certain items operate using the charge of cores and is consumed in the crafting process of magical tools. 

Roy made sure to read through the descriptions twice over. Nothing was indicating that a living creature could absorb the mana or what it would result in. With the one the treant had nearly depleted, Roy attempted to draw the mana himself, as his own reservoir was not yet recharged but found he could not. This meant he either did not know how or lacked the ability to, giving him worry that the treant might start growing from that. 

It felt like a waste consuming the core dropped by the shaman as being able to shoot fireballs would be very useful but, without a means to make something out of it, however one did, consuming it was probably the smarter option. For now, though, he had three other cores to use first. 

For heading down into the cave, Roy really wanted a light source. At first, he tried a brightstone from another world he had been to but received an error. A bullseye lantern was what he wanted, but he lacked a fire source. He could make one out of a different core, but it felt like a waste. 

Instead, he took a moment to experiment, testing the extent of what was allowed to create before an error popped up. In doing so, he discovered two things. The first was a limit to the size and mass of the object, which seemed to be determined by the charge of the core. The second was the number of what constituted an object. The input seemed to require whatever was considered a whole concept. The lantern, for example, could be filled with oil, but if he tried to just get oil, he could not add a lantern after the fact. He would have to be intending to create a lantern from the start. He could, however, seemingly get the oil contained within a barrel if he thought of an oil drum. 

It was overall slightly odd and a little confusing, but the best he could do was create an already lit lantern. After confirming it was possible, he set it aside for the moment and considered what else he could make. 

A pair of shoes, boots preferably, would be a pleasant relief for his feet. He was pleased to find that a pair of boots was accepted without issue, rather than having to create two individual ones. 

Lastly, something to protect him from the heat, but for the moment, as he was intending to head into the cave, he decided to hold off on it just in case. 

He reckoned he would soon need to turn one into a bag and food, as well as a flask if he left the river. Those buckets, which he had tossed aside just before kicking the treant down the hole, were not going to cut it. 

Roy took the shirt off his head, glad to see it was only singed, probably from being wet earlier, and began tying the sleeves together. He then tied the bottom closed as best as he could and strung it over his shoulder as a makeshift handbag. He then placed the shaman's and the depleted core within to keep them safe from the treant, and whoever, or whatever, took the wooden strips. 

Holding out one of the cores, with the treant watching it carefully, Roy pictured leather boots which he hoped would fit. He then let them form, and the core once more morphed into the correct shape. He moved his hand to grip them at the top, as they remained floating in the air during the transformation. 

Not wasting any more time, he hurriedly put them on, glad to find they were how size and wound the shoelaces around the hooks before tying them. 

Retrieving his dagger, Roy was now prepared, with all of his equipment at the ready. Buckler and dagger in his left, and spear with the extra core in his right. He walked up to the cave entrance, leaving the treant behind this time, and listened while he let his eyes adjust to the darkened interior. 

Roy had contemplated dropping the treant down there once more but decided that a third time, especially after that last party, would be too suspicious for any to come out again. And if he had to go in, he would rather not have his descent heralded by the tree. 

With a slightly better view of what lay ahead, with his eyes adjusted, it revealed a rocky slope leading down, as if the cave entrance had once been a wall that collapsed inward. He held the image of a lit lantern in his head as he began a slow and careful descent, ready to form it if he needed the light. 

The slope was about ten feet high, and he had managed to scale down it without dislodging any of the rocks, despite his hands being occupied. He had nearly clattered the spear tip against one of the walls a few times, however. 

While the climb had been down a slanted shaft, the bottom was like an oval room that opened up into what appeared to be a large chamber with a pool of water in it, emanating an azure blue much like the cores. It illuminated the cave walls and ceiling, creating beautiful, swirling patterns as the surface of the water rippled. Blue moss seemed to be growing around the edges and some floating on the water. 

There were also three plants that he could see growing out of the water with tall, sprawling roots holding them up above the surface like legs. They all converged into a single pure white stem that grew outward, giving them a blue mushroom head on top. 

While intrigued, Roy did not examine them yet, as he did not want the interface blocking his view. He pushed himself up against one of the walls of the chamber he was in and peered around the corner. To the left was just water all the way to the wall. To the right was a small ledge that led around and to a wide bank, which had another tunnel in the back. 

The entire chamber was empty and quiet save for the soft sound of water trickling somewhere. Roy stepped out, careful not to slip on the wet rocks as the water had splashed, and approached the tunnel. 

He was not even halfway there, however, when a goblin turned the corner and saw him. This one looked different from the ones he had seen earlier, not in the way of how he was dressed, but his obvious age. 

He had a walking stick, which clattered to the ground as his eyes bulged wide. His knees trembled, and his saggy skin twisted into pure shock. He was also hunched over, making him even shorter than the others. 

But this did not deter Roy from thinking it was dangerous, as a fire blast could come at any moment, and pulled back his spear to throw. He stopped, however, at the very last moment, nearly dropping the spear as the goblin lowered its head, raised its hands, fell to its knees, and began speaking. 

"Please," it begged in a raspy, scraping high-pitched voice. "Mercy."