Mo Xi thought for a moment and then said, "You are all right. However, before we communicate with the other two realms, we still need to further investigate the origins of this mysterious force. I think we can start with the black-robed man. Perhaps we can dig out more clues."

Mu Li also said, "When I was snooping into the black-robed man's memories, I saw an ancient altar. Those mysterious people seemed to have awakened some kind of power there. Perhaps we can start our investigation by looking for this altar."

The ghost kings all expressed their approval. Therefore, Mo Xi arranged for the ghost messengers of the underworld to secretly inquire about the news of the ancient altar in various parts of the underworld, and at the same time strengthen patrols on the border of the underworld to prevent sudden attacks from mysterious forces.

Mu Li and Mu Yang were in charge of interrogating the black-robed man. They imprisoned him in a secret cell in the underworld, which was made of special materials that could restrain his power.

Mu Li walked into the cell, looked at the imprisoned black-robed man, and asked coldly, "You'd better tell me the truth. What conspiracy are you plotting? Where is that ancient altar?"

The black-robed man raised his head, a trace of resentment flashing in his eyes: "Humph, do you think you can find out everything by catching me? I won't tell you."

Mu Yang stepped forward and threatened: "Don't refuse a toast and then drink a forfeit. The underworld has plenty of ways to make you speak."

The black-robed man sneered, "You can torture me as much as you want. Since I dare to do these things, I am not afraid of your punishment."

After learning that the interrogation had reached a stalemate, Mo Xi decided to come in person. He looked at the man in black robes and said, "Do you think we can't do anything to you if you don't tell us? We already have some clues, and we're just giving you a chance to confess and get some leniency. If you persist, you will face even harsher punishment once we've investigated everything."

The black-robed man remained silent, a hint of hesitation in his eyes. Seeing this, Mo Xi continued, "If you follow that mysterious master, will he really fulfill his promise and make you one of the rulers of the new world? You're just a pawn. Once he achieves his goal, do you think he'll let you go?"

The black-robed man trembled slightly after hearing Mo Xi's words, as if his heart was touched. He lowered his head and fell into deep thought.

After a long moment, the black-robed figure slowly raised his head, a hint of helplessness in his eyes. "Alright, let me tell you. That ancient altar is located deep within the freezing cold of the underworld, protected by powerful restrictions. The altar is where we awaken that power. As for what that power is, I'm not entirely sure. I only know that the mysterious master has been searching for a way to open a certain seal, and this seal seems to be closely tied to the fate of the three realms."

Mo Xi and the other two looked at each other, and saw solemnity in each other's eyes. It seemed that the matter was far more complicated than they had imagined.

"Then what is the relationship between the power you awakened and the chaos in the Yin and Yang world?" Mu Li asked.

The black-robed man replied, "That power can disrupt the balance of the Yin and Yang Realm. The mysterious master wants to create chaos in the Yin and Yang Realm to trigger a chain reaction in the three realms, thus creating the conditions for him to open the seal."

After Mo Xi and the others obtained these crucial clues, they immediately informed the other Ghost Kings. After discussion, they decided that Mo Xi, Mu Li, and Mu Yang would lead a team of Underworld elites to the extremely cold land to uncover the secrets of the ancient altar and stop the mysterious force's next move.

Mo Xi and the other two knew that this matter could not be delayed and immediately prepared to set off. They were well aware of the danger of this mission, but for the sake of peace in the three realms, they embarked on the journey to the extremely cold land without hesitation...