"I was half-worried that the water would start pooling into these tunnels around us," Kane told Rui when he returned back to him.
"Nah, don't worry, I made sure that there was no way that that could happen, there are plenty of tunnels leading deep down into the dungeon, so we'll be fine," Rui reassured him.
He turned towards the lake. "I knew that this was not going to happen instantly, but damn, it's a ten-meter wide hole and the rate at which the water levels are receding is painfully slow."
The water level was falling a few centimeters every second, which indicated just how enormously wide the lake was, given that water was gushing out of a ten-meter-wide hole.
"It's just a matter of time now," Kane shrugged, before leaning against a tunnel wall.
Rui could already see esoteric ore deposits slowly starting to emerge now that the water levels were receding. Though it still was too dangerous to try and extract them given the fact that they could still be attacked if they were close to the water.
He ran his Riemannian Echo sense through the water as he studied the reactions of the various aquatic and amphibian monsters and creatures in the lake.
"They sure are panicking," Rui remarked.
Most of them had grown erratically active, understandably. The many creatures had probably not encountered a time when the very medium they had existed their entire life pulled them downwards with such a great force. If they simply remained still, they would get pulled down.
Thus each creature had gotten into a frenzy to stay as high up as possible. Fish began migrating higher and higher as the lake was getting dragged down lower and lower. Many amphibian creatures had already begun moving out of the water in order to avoid the powerful pulling current, although none of them had noticed Rui and Kane standing at the entrance of a tunnel to the floor.
Rui couldn't help but feel curious about the psychology of these creatures. To them, was water truly no different from air? From their perspectives, were they effectively floating and flying midair when they swam around in the water?
In that case, their circumstances would be even more inconceivable to them than he had perhaps suspected.
Just as Rui was about to relax as he waited for the water to drain, he noticed something strange.
"Hm?" He furrowed his eyebrows. "Have the water levels stopped declining?"
"I can't really tell…" Kane squinted his eyes.
"They have…" Rui mumured as he swept his Riemannian Echo technique at the bottom of the lake where the hole was. "Wait a second, the hole… is blocked!"
Kane frowned. "By what? A rock?"
"No," Rui shook his head. "A creature blocked it. It looks like a giant octopus."
Rui could clearly sense a large octopus-like creature settling on top of the hole, squeezing down on it with its entire body. It used its tentacles to seal down the edge of the hole, making sure that no water could leak through the hole at all.
Rui was impressed. The creature correctly identified the source of the problem and realized the gravity of the situation before coming up with a quick solution.
('Octopi always have been clever creatures back on Earth,') Rui recalled watching some videos on Youtube where an octopus would solve some complex problems and puzzles. ('It appears that those traits exist in this world as well.')
"A creature voluntarily blocked the hole?" Kane raised an eyebrow. "Are you sure that it isn't just stuck?"
"Yeah," Rui nodded. "For one, octopi have extremely flexible and ductile bodies. The notion of them getting stuck is practically impossible. For another, this octopus looks like it's trying everything in its power to ensure that the hole doesn't open up."
"That's not good for us, is it?" Kane sighed
"Not one bit I'm afraid," Rui chuckled, but there's a pretty simple solution, although it's a pain in the ass,"
"Going back down and slicing him up?"
Rui quickly returned back down to the tunnel network where the hole was.
Thankfully, because the octopus was blocking the hole, thus the tunnels were not filled with water. The were many creatures en route, that had been left in the tunnels when the octopus closed the hole. He sky-walked to avoid getting wet and the corpses, before reaching the hole.
"That looks painful," Rui winced as he saw the octopus' abdomen stuck in the hole.
He drew his sword. "Not as painful as this, though."
Three rapid strikes created deep gashes in the body of the octopus. The octopus' body internally cleaved apart as the cold bellhorn steel of his blade repelled the esoteric substances in the octopus' body on either side of the blade in the opposite directions.
Consecutively, the wound extended far deeper than the blade's length, killing the octopus on the spot.
Rui immediately dashed away from the site as the octopus' corpse fell through and the rush of the water flooded through, immediately reclaiming the tunnel as it completely consumed it.
Rui gritted his teeth as he barely managed to avoid it. This time, he was sky-walking instead of running on land due to the fear of potentially slipping on the wet tunnels.
A small wave splashed onto Rui's lower half as he escaped up into the tunnel.
"Tsk," Rui tutted. "That was annoyingly close."
He pulled out his hot air pipe, before inhaling and heating himself dry.
It wasn't long before he returned to Kane. The two of them waited as the lake drained itself. Rui kept a sharp watch to make sure that there were no more creatures attempting to block the hole as before.
It took about an hour, but the lake was finally drained.
"Alright, let's get this over with," Kane was about to jump into the emptied lake.
"Wait," Rui stopped him. "I think you should do the mining."
"Huh?" Kane tilted his head in confusion.
"I think I should explore the unclogged parts of the dungeon before the water is gone."