Klein listed four sets of items in the trading channel. If all of them were successfully exchanged, he would be able to obtain ten runes.

Before Klein headed to the next catacomb, the system sent back the news of the successful exchange.

[Wind Rune+1]

[Water Rune+2]

[Rune+1]

Four sets of items were sold consecutively.

Among them, the Kobold meat was the first to be sold out!

It was evident that everyone valued the price-performance ratio more. As for how it tasted, whether it was disgusting or not, they didn't care.

Survival was more important.

Although it was a Kobold, it wasn't a human. Under extreme hunger, it could still be eaten.

With four sets of runes in his hands, all he needed to do to use the low-grade rune base upgrade scroll was to obtain another wind rune!

At this moment.

Klein was holding a runic lamp as he explored the twenty-second catacomb.

This catacomb only had a bronze treasure chest.

The other four directions were either empty, or there were only crypt creatures and no resources.

When opening the treasure chest, Klein hoped to open a wind rune, but the result wasn't satisfactory.

Not to mention the wind rune, there were no other elemental runes either.

There were only some materials and two bottles of milk.

At this point, Klein only had three excavations left for today.

Klein encountered a difficult problem in the next subterranean cavern.

[Continue digging down. The poison gas will suffocate you to death.]

[There's an iron treasure chest in the subterranean cavern ahead. It might yield good items. It would be dangerous to enter now. There are two Night Whistlers lurking in the darkness. They can display their ferocity at night.]

[The subterranean cavern behind is empty.]

[Excavate to the left. There's a wooden treasure chest that can be opened.]

[There's only barren soil in the catacombs on the right, as well as some animal traps.]

Of the five directions, the catacomb in front had the best supplies. There was an iron treasure chest.

Klein didn't pay attention to the other directions.

However, heading to the catacomb ahead was risky.

Klein could either wait until daybreak before excavating the catacomb ahead, or he could head to the catacomb on the left.

He could wait until daybreak to obtain a stable income from the iron treasure chest.

If he continued digging, he would have to try his luck. Perhaps the resources he would excavate the next three times wouldn't be as good as an iron treasure chest!

'Forget it. Let's call it a day. I'll excavate the catacombs in front of me at daybreak.'

Klein was still a little unwilling.

Light.

He opened the biological atlas and looked at the information on Night Whistle.

If it was lurking in the darkness, wouldn't he be able to illuminate it with his runic lamp?

Klein searched with questions.

The results were out.

[Night Whistle: A creature that looks like a wolf or a lizard. It is completely black and has wings. When night falls, it will enter a berserk state. Compared to its daytime self, they are two different creatures.]

[Ability: Night Berserk]

[Weakness: Daybreak Weakening]

[Danger Factor: 15/35]

Daytime Danger Factor: 15. Nighttime Danger Factor: 35!

Compared to nighttime, daytime and nighttime were indeed two different creatures.

There were two Night Whistles in the basement.

The degree of danger was self-evident.

Furthermore, they had wings and could fly.

Klein's advantage in the air was completely gone.

He thought for a moment before saying, "It's simply the opposite of a Carrion Jackal."

"No, the Night Whistle is at least better than a Carrion Jackal during the day. Carrion Jackals are weak at night and can only roar."

After reading the information, Klein dispelled his only thought of taking a risk.

If the Night Whistles didn't have wings, he could give it a try, but they did so there was nothing he could do.

First, he turned on the water condenser and added 40 pieces of wood.

There was still a long night ahead.

Klein continued to immerse himself in practicing his blade and crossbow.

During this process, he could clearly feel the effects of the strength talisman.

The runic speed blade in his hand became lighter and lighter.

He did more than a hundred push-ups without even taking a breather!

He trained for more than three hours in a row.

Klein was tired.

The runic crossbow's 100-shot limit was exhausted, so he could only add another soul.

He was covered in sweat, and his clothes were dirty to a certain extent.

Klein dipped a towel into the water and wiped his entire body.

If it weren't for the fact that there wasn't too much water, he would have wanted to take a good bath. It was already quite extravagant to use clean water to wipe his body.

Others wouldn't dare to do so. They wished that every drop of water could be used to drink.

The used sewage couldn't be poured out, so he washed his clothes and pants. Finally, he used some water to do a simple wash.

As for drying them, it could be set up by the campfire outside the base.

Furthermore, Klein could make clothes.

After consuming three pieces of cloth, a piece of lizard skin, and six cotton threads, a set of close-fitting clothes appeared in front of him.

It included: shirts, pants, underwear, socks, and shoes.

It was a five-piece set.

Klein changed into clean clothes and felt much more comfortable.

Klein woke up early in the morning.

There were a few transaction records in the system notification record.

After a night, all the items on sale were sold out.

He obtained two wind runes, one water rune, one fire rune, and two earth runes once again!

With the original runes, Klein now had four wind runes, five water runes, five fire runes, and six earth runes.

Klein didn't bother to wash up and took out the low-level rune base upgrade scroll.

[Low-Grade Runic Base Upgrade Scroll: Water Rune 5/3, Earth Rune 6/3, Wind Rune 4/3, Fire Rune 5/3, Soul 12/5, Iron 68/50, Copper 61/50, Stone 80/50, Wood 22/50, Sand 100/100]

He had used 40 wood to make water last night, or he would have had enough materials.

This matter was easy to resolve.

Klein directly put up a piece of fine Single-Horned Sand Hound meat onto the trade channel.

Half a piece of Sand Hound meat for 50 pieces of wood, and the stock was 2.

In less than a minute, two and a half pieces of Sand Hound meat were sold.

With that, the materials requirements for the upgrade scroll had been met.