There were a full four hundred-plus Ink-Expelling Ships, and every single one of them required him to personally work on them — to seal the Purifying Light and set up the Heaven and Earth Formation.
Sealing the Purifying Light wasn't particularly arduous. All he had to do was activate the two marks on the back of his hand to draw upon the power of the Yellow Crystals and Blue Crystals, merge them together, and the Purifying Light would naturally form. But the Heaven and Earth Formation on each Ink-Expelling Ship had to be personally set up by him.
This was absolutely a monumental undertaking. Yang Kai estimated that it would take at least three to five years to finish.
And this was only the initial construction — it wasn't as though he could rest easy once it was all done.
The Purifying Light would be consumed over time. When the Purifying Light at the various passes was used up, they would inevitably have to come to Azure Sky Pass to have him replenish it.
Even though Yang Kai possessed countless Yellow Crystals and Blue Crystals, he couldn't help feeling somewhat worried.
At this rate of consumption, no matter how many Yellow Crystals and Blue Crystals he had, the day would come when they were all used up. When that time came, where would the humans of the Ink Battlefield turn?
Perhaps before that happened, he could return to the Three Thousand Worlds and seek out Brother Huang and Sister Lan in the Chaotic Dead Zone?
But these were not matters that needed immediate consideration. The Yellow Crystals and Blue Crystals he currently possessed could still last for quite a while.
Yang Kai also asked about Qing Kui and Su Yingxue. Xu Linggong simply said the two had been left behind to garrison Yin Yang Pass and had not accompanied him on this trip. Learning that they were both safe and sound, Yang Kai felt relieved.
After chatting for a while longer, Xu Linggong took his leave, ultimately never bringing up the matter of having Yang Kai accompany him to Yin Yang Pass.
The next day, Yang Kai received orders to head to the central plaza, with Feng Ying accompanying him.
When he arrived, he found Ding Yao already waiting there. Beside him stood a tall, imposing middle-aged man clad in golden armor, his aura deep and unfathomable — clearly another Eighth-Order Open Heaven. Judging by his appearance, he was likely an Eighth-Order from the Great War Heavens.
Lined up behind the two men were four brand-new Ink-Expelling Ships, identical in design and size to the ones previously built at Azure Sky Pass.
Yang Kai knew these must be the Ink-Expelling Ships the visitors had brought.
Ever since the Ink-Expelling Ships had been constructed at Azure Sky Pass, messages had been sent to all the human passes to inform them of the ships' purpose. Along with the messages, the blueprints for the Ink-Expelling Ships had also been transmitted.
Every pass had taken the news seriously. Once they confirmed the information was accurate, they immediately began construction, then had their Eighth-Order cultivators carry the completed ships to Azure Sky Pass for refinement and completion.
And this refinement process could only be performed by Yang Kai.
Upon approaching, Yang Kai bowed. "Senior Ding!"
Ding Yao nodded slightly. "You know why you've been called here?"
Yang Kai nodded. "I do."
"Good." Ding Yao sighed. "The Ink-Expelling Ships have proven their immense value in the recent battles. They are a fundamental weapon for our humanity to overcome the Ink Clan. Building them isn't difficult, but the final refinement requires your hand. You may have to work harder going forward."
Yang Kai clasped his fists. "As a Disciple, it is my duty and I will not shy away from it."
"Excellent!" Ding Yao gestured to the middle-aged man beside him. "This is Wei Junyang from Great War Pass. He is also my senior brother. Great War Pass is currently engaged in battle against the Ink Clan army and is under considerable pressure. They urgently need the support of Ink-Expelling Ships."
Wei Junyang's expression was solemn. He clasped his fists toward Yang Kai and spoke in a deep voice. "Junior nephew, the safety of thirty thousand warriors at Great War Pass is in your hands!"
"Senior flatters me. What I can do within my ability is merely my duty," Yang Kai replied modestly. "Since Great War Pass is currently engaged in battle with the Ink Clan, we should lose no time. Shall I begin now?"
"Splendid!" Wei Junyang nodded quickly.
"Have you brought the necessary materials?" Yang Kai asked.
Wei Junyang promptly produced a spatial ring. "All the materials for setting up the Heaven and Earth Formation are inside. If you need anything else, don't hesitate to let me know."
Yang Kai reached out and took the spatial ring, sweeping it with his divine sense. He nodded. "This should be about enough. If it falls short, I'll let you know, Senior."
With that, he flickered onto the nearest Ink-Expelling Ship and used the spatial formation on the deck to teleport into the cabin.
The preparatory work on Great War Pass's Ink-Expelling Ships had been done well — everything that could be set up and constructed was already in place. All that was lacking now were the Heaven and Earth Formation and the Purifying Light.
And these two things were precisely what Yang Kai had to handle personally.
Watching Yang Kai disappear inside, Wei Junyang let out a soft breath of relief and turned to Ding Yao. "Junior brother, how long do you think this will take to complete?"
The battle at Great War Pass was at a critical juncture, and naturally, he hoped to return as soon as possible.
Ding Yao replied, "It shouldn't take too long, though I'm not entirely sure of the exact time." As he spoke, he turned to look at Feng Ying standing nearby.
Feng Ying understood the cue. After a brief moment of thought, she said, "It takes about six or seven days to set up one Ink-Expelling Ship."
Wei Junyang's thick eyebrows shot up. "Six or seven days per ship — that means four ships would take at most a month."
A month was not particularly long for a battle that could last years — it was a wait they could afford.
Ding Yao said, "Senior brother Wei, why don't you go back and rest for now? Once things are ready here, you can come and collect them?"