"The river surrounding the entire city is called the 'Soft River'. It divides this fierce city into two parts, with the upper part inside the river as the upper city area, and the lower part outside the river as the lower city area. Although we haven't issued any explicit instructions, the rich and powerful live in the upper city area, while the poor and weak are concentrated in the lower city area. This situation has naturally formed." Tian Lu pointed to the wide and clear river outside the carriage as she introduced.

After dining at the mansion, the Yunlan sisters suggested taking Mu Zhou on a tour of the city, with them serving as the guides. Mu Zhou eagerly agreed, as he hadn't had the opportunity to explore the city properly before due to being caught up in various chaotic events.

"Although the layout and environment of the upper city area is indeed much better than the lower city area, most of the major trade and city defense matters are carried out in the lower city area. Additionally, most of the hiring guilds are also located in the lower city area." Tian Lu jovially explained inside the luxurious carriage.

"When this city was first built, it was actually very small, about the size of a large settlement. Later, under the leadership of Ling Po Po and Kaili Kailu, it gradually expanded. The population also grew, and now there are millions of people. The city has expanded countless times, and it takes nearly a day to travel from the west to the east of the city!"

"Wow, that's truly an astonishingly enormous place," Mu Zhou sighed as he looked at the scenery outside the carriage. In his world, there were indeed cities with millions of inhabitants, but how could that convenient era compare to this?

"Yes, we can already see it. That's the very center of the city, the 'core' of the city," Tian Lu pointed to a high tower ahead.

Before this trip, the Yunlan sisters had informed Mu Zhou that this was their destination and the only place in the whole city that could be called forbidden.

The carriage stopped next to the high tower, surrounded by strict guards. However, upon seeing the car symbolizing the Yunlan sisters, the guards respectfully saluted and let them through.

Previously, it didn't seem that big when they were far away, but once they got closer, Mu Zhou realized that the tower was actually quite enormous. Its base shimmered with various magical lights, and Mu Zhou could feel the energy converging towards the tower from under his feet.

Although this world didn't use steam or electricity, it had a special energy source called 'crystal energy'. Just like its name suggests, it is an energy crystal similar to a crystal and is produced in specific mountains or underground areas.

In human research, these crystals can be transformed in various ways to make magical artifacts or high-end luxury goods. For example, lighting tools, and some spellcasters use them as mediums, of course, they are extremely expensive.

These crystals can come in various sizes, but bigger ones always contain more energy. The one in front of them was extremely rare, being taller than a person and having high purity. The energy contained in it could even be used as the core to activate the energy of an entire region.

"Surprised? This is our Lielie City's treasure! The defensive facilities powered by the energy it provides make it easy for us to deal with most small-scale monster invasions without even lifting a finger!" Tian Lu looked at the crystal, her face radiant.

"And, it is crucial for us, the sisters!"

"Crucial...huh?" Mu Zhou felt the connection between the energy in the crystal and the Yunlan sisters.

"You... rely on it," Mu Zhou observed the crystal and said with certainty.

"Huh? Mu Mu, although you don't possess battle aura or know magic, you have a keen perception," Tian Lu looked at Mu Zhou with surprise and then touched the crystal with her hand.

"That's right... we do rely on it. But this is a secret, Mu Mu, don't tell anyone else, okay?"

"You..." Mu Zhou didn't know how to continue speaking.The conjoined sisters will feed on each other and eventually wither away, and in Mu Zhou's "memory," there are only a few methods that can completely solve this. However, in this world, this situation seems to be unsolvable, and can only be alleviated in some special ways.

For example, the two sisters can attach themselves to a powerful individual at the same time, absorbing the energy from this individual and using it to force a balance in their mutual devouring. This individual will bear the cost of their mutual consumption.

If this situation can continue, it would be a good solution. However, in reality, this is unlikely to happen because there are very few individuals who can constantly bear this cost.

This crystal contains traces of energy, but it is also nearing its limit. The talents of these two sisters are surprisingly high, and even if they don't deliberately cultivate, this crystal is already struggling to bear their energy.

This method of attachment is almost impossible to use a second time. Once this crystal can no longer bear it or is destroyed, the balance between the sisters will be instantly broken, and the two conjoined flowers will begin uncontrollably devouring each other, resulting in their deaths in a very short time.

In short, if the city is destroyed, they die. If the city is not destroyed, their time is also limited.

Tianlu smartly reads what Mu Zhou wants to say from his expression, but she doesn't care. No, it's not that she doesn't care, but that she has already accepted her own fate because they are clearer about their own situation than anyone else. She even joked with Mu Zhou.

"You see, we don't have many days left. Mu Mu, why don't you join us? Let's make the most of our time and do some wonderful things."

Although Mu Zhou hasn't known the Yunlan sisters for a long time, he likes them very much and already considers them good friends. After learning about their tragic situation, he couldn't help but feel a bit heavy and even a little annoyed.

"Let's forget it. When will you two change your bad temper?"

"Oh? Why are you like this? Both my sister and I really like you."

Mu Zhou reached out and touched Tianlu's soft pink hair, looking into her clear eyes. "How about giving up this city and using the remaining time to do what you want?"

Tianlu's expression slightly converged, and she stared seriously at Mu Zhou. "That won't do. We promised to protect this city, which is almost as important to us as each other."

Mu Zhou watched her for a while and nodded. "I see."

In the following days, Mu Zhou and Talisa lived comfortably in the Yunlan sisters' castle, enjoying noble treatment. Meanwhile, the Yunlan sisters became busier and could hardly be seen. The seriousness on their faces grew with each passing day.

Mu Zhou also met the other protector they mentioned, Granny Ling, an older woman. Mu Zhou initially thought she would be an old man with deep city planning skills, but after a few encounters, he found out that she wasn't like that at all. She genuinely cared about and worried for the city, as well as sympathized with the situation of the Yunlan sisters. She was a good person.

Granny Ling asked Mu Zhou some strange questions, asking if he had a strong companion skilled in physical techniques, which left him confused.

On the fourth day, news arrived that the monsters were approaching The Domain, and there were many more than expected!

At the same time, the last protector of the city was surrounded by monsters while gathering information and although she managed to escape and deliver the news, she was severely injured and unable to fight.

In the early morning, the Yunlan sisters came to Mu Zhou, their faces grim, and said seriously, "Mu Mu, let your companion take you and escape. He should be able to do it. Leave this to us."

Mu Zhou got up from the bed, stretched lazily, and smiled mischievously at the Yunlan sisters.

"Don't be silly. I'm going to show off now."