"That is a river of Qi. A river of pure yin Qi,

" Ensis said somberly.

"Yin Qi?!

" Hao Xuan repeated, shocked.

In nature, Yin and Yang existed opposite to one another. Yin was of the cold attribute (generally) while Yang was hot. Yin was negative, and Yang was positive. Yin was black, and Yang was white.

Under normal circumstances, one element couldn't exist without the other. They were both two sides of the same coin.

Their duality was considered to be the balancing force of the universe. Without good, there was no evil. And without evil, there was no good.

Yin could not exist without Yang in nature. And an entire river of Yin Qi like this was certainly not possible.

But the most important part was that Yin was the dark element. Creatures that lived in the darkness and survived off of negative emotions were of Yin element.

"The cold, this is where it's coming from?

" Hao Xuan finally realized.

No wonder the deeper he went into the cavern, the colder he felt. If Ensis had not cut off his arm, he probably would have received a lot more damage overall, especially if the Yin Qi had managed to enter his body.

With a simple indirect touch, he had almost lost his life there, what would have happened if he had actually put his hand in there?

As he realized this, the anger he was feeling towards Ensis vanished like smoke in a storm.

"Hey, thanks,

" he looked at Ensis in the eyes and thanked him from the bottom of his heart.

"It is my duty,

" Ensis bowed as usual, not feeling like he had done anything special at all. He was just doing his job.

Hao Xuan couldn't help but shake his head at his response. He wished Ensis would act a bit more like a normal person. It would be too boring otherwise...

They both backed up several dozen meters and Hao Xuan had to take out some more medical supplies. He bandaged the stump after applying some medicine, as the blood he had in storage was nowhere near enough to grow it back.

*Gurgle~*

The entire cavern slightly shook as a loud gurgling sound came from the other end of the Qi River. The amount of Yin Qi reduced so quickly that Hao Xuan could see it with his naked eye. It looked like someone had opened the dam doors and within five minutes, the river had lost over a third of its volume.

Its speed had decreased significantly as well and it looked like a stream rather than the raging river of before.

Ensis closed his eyes and listened carefully. His ears twitched,

"There seems to be an opening over there, about three kilometers down,

" he pointed in the same direction the river was heading to.

Hao Xuan clenched his fist in anticipation,

"Great, let's go. Follow the river!

" he ordered.

Ensis took out his sword and started cutting off large chunks of rocks and ice, making a small pathway along the river. It was just enough for one person to walk through at once and was relatively safe as well, as long as no one fell into the river.

Although the distance to the opening was only three kilometers, in total it took them about six hours to reach the other end.

The river opened up into a massive room that was several thousands of meter long.

There were large mechanical arms all along the sides and the roof. Long tracks were inlaid on the floor that were probably used to transport materials from the looks of it.

There were two rows of lights on the roof, some were on while most were off with a couple blinking randomly.

There was a layer of dust on the ground indicating that no one had moved past here in a long time.

"Do you see anything dangerous?

" Hao Xuan whispered towards Ensis, who shook his head.

Letting out a sigh of relief, he jumped into the room as there was about a fifteen-meter gap between the Qi river and room.

"Woah,

" Hao Xuan was amazed by the machinery he saw. They looked very futuristic and were completely scratchless.

He channeled the force Qi through his arm and tried moving one but couldn't even make it budge even with his full strength, which was enough to throw a semi-truck dozens of kilometers in the air.

"Damn it, they look so cool. I bet they would go for a high price back on the beast world,

" he mumbled.

"Remind me to take these with us when we leave,

" he said to Ensis before walking off along the tracks.

Every few hundred meters there would be a kind of storage room to the side. He checked every single one of them but they were all empty. There were only a few metal boxes and containers left which he took without complaining. Even their metal looked extremely sturdy and he could barely make a dent with his full-powered punch.

"This is good, very good!

" he mumbled while rubbing an empty container. Ensis looked on speechlessly as he had never seen his master act so...greedily before.

About 50 minutes later the room finally separated into three small hallways. Two of them had flickering force fields outside while the one on the right was open. It seemed like the energy that was powering it had run out.

"Attack that one, see if you can break it,

" he pointed at the one in the middle.

Ensis took out his sword and fired off a black sword wave. But as soon as it came into contact with the forcefield it disappeared. With a deep frown, Ensis fired another one but the result was the same.

Finally he couldn't take it anymore and actually physically attacked it with his sword. It seemed like he had hit a wall made out of water and all the energy was instantly absorbed by the shield.

"Stop stop, it's not going to work,

" Hao Xuan shouted when he felt Ensis's aura increase several-fold.

"There's one already open, we can just check here first.. Let's see what the 'Collector of species' has left in inventory for me to take,

" he grinned and walked into the rightmost hallway.