Heavenly dao was the law of heaven, which could also be seen as the heavenly rules and restrictions.
Wu Yu was the heaven within his Devouring Apotheosis Realm. He was the will of the whole apotheosis realm.
He currently had many immortals in his Devouring Apotheosis Realm, but it would not be so easy for them to progress past ordinary immortalhood.
He had to make the Sea of Heavenly Dao in order for them to continue progress.
This was a fairly difficult process. Luckily, Wu Yu devouring many eternal demon emperor corpses had given him some knowledge on the process.
From lesser daos to the creation of a heavenly dao required a very long time, before one could finally cumulate all of the learnings in the Sea of Heavenly Dao. That would create heavenly dao and rules within the Devouring Apotheosis Realm that the immortals themselves could learn and improve from.
If he could create the Sea of Heavenly Dao, then there would be essences of heavenly dao in his world.
For example, wind, fire, water, and earth; wind, snow, lightning, and thunder; or even fighting and killing. Each element could be divided into many daos that could help the immortals in his Apotheosis Realm to rise higher.
Everything had its own dao, and to realize them together as the Sea of Heavenly Dao took ages!
There was actually Sea of Heavenly Dao in the Heavenly Domain, except that Wu Yu had not known about it before. All of his dao from the Nine Xuan Dao Realm had come from the Sea of Heavenly Dao of the Heavenly Domain.
He had to understand all of the dao in the world, and then integrate them into his own Sea of Heavenly Dao.
If he missed even a fraction of the daos, he would be unable to complete his Sea of Heavenly Dao.
Ordinary immortal emperors found the leap from sixth to seventh tier incredibly difficult. They would take hundreds of thousands of years to even comprehend some of the heavenly daos.
One could imagine how difficult it was to have to learn them all!
For Wu Yu, the solution to this breakthrough was through devouring, and he did not even have to devour any more.
Wu Yu had devoured a few seventh tier eternal demon emperors, and their corpses held heavenly daos.
Wu Yu had absorbed all of their profound wisdom and made it his own understanding.
Therefore, he only needed 30,000 years to put all of the heavenly daos into his Devouring Apotheosis Realm.
As all of them combined, an intangible Sea of Heavenly Dao appeared in his Devouring Apotheosis Realm!
As it appeared, Wu Yu's Devouring Apotheosis Realm was finally supplemented with a higher order.
It was something that the immortals in Wu Yu's Devouring Apotheosis Realm could sense. They began to study the heavenly daos and increase their own cultivation realms!
Through devouring, Wu Yu had successfully created the Sea of Heavenly Dao and become a seventh tier immortal emperor.
The immortals in his apotheosis realm continued to grow stronger, and he too began to grow stronger, feeding off their power.
His sixth tier Supreme Buddha Immortal Realm and seventh tier Eternal Immortality Realm could combine to bring forth even more startling powers.
Xuanzang, Buddha Above All sensed Wu Yu's breakthrough.
He soon appeared to Wu Yu. After congratulating him, he said: "Wu Yu, you must learn to control your new powers through practice. Why not fight Dipankara, the Lamp Bearer Buddha, to familiarize yourself with your seventh tier powers?"
"Who is Dipankara?" Wu Yu asked, his interest perked.
Very soon, a black immortal buddha appeared, bearing a lantern aloft.
The Dipankara had a stern expression, and the lantern he bore was said to be an epochal immortal treasure. Within it, an eternal flame burned.
As long as the flame did not go out, the Dipankara would not die.
Wu Yu saw that the fire in the lamp was linked to the Dipankara's buddha world.
"The Dipankara is an eighth tier Supreme Immortal Buddha Realm cultivator! He will be a good sparring opponent."
Wu Yu said, itching to get started.
He could feel that his apotheosis immortal energy had swelled correspondingly after his Sea of Heavenly Dao was completed. His Unshackled Doppelganger alone could probably produce more than 10 million clones.
His other techniques would definitely have grown stronger as well.
The Dipankara's immortal buddha trueform sat on the black buddha world, bearing the lamp.
The lamp burned strongly, radiating an everlasting, enduring power.
With Xuanzang watching over them, Wu Yu prepared to fight Dipankara.
Wu Yu had tasted the immortal buddhas' way of fighting before, but this Dipankara was one of the ancient and powerful immortal buddhas, and definitely a cut above the others that Wu Yu had encountered so far.
If Wu Yu could defeat him, it would prove his entrance into an even more elite tier.
Of course, this "elite" status was only a rough gage. Besides, he was definitely still far from comparing to the true powers like the Jade Emperor or Xuanzang.
Still, if Wu Yu won here he would be able to roam Heavenly Domain more or less freely, as long as he avoided the Jade Emperor.
"Let's see what you've got, Dipankara!"
Wu Yu thought. He picked up his Ruyi Jingu Bang.
Without hesitation, he leapd forwards, calling forth golden buddha light that arced out towards the Dipankara's black buddha world.
The Dipankara's frown deepened on his impassive face. The lamp in his hand suddenly illuminated the entire area.
Within Expanse of Nirvana, the lit up space caught fire spontaneously. The combustion managed to stop the Ruyi Jingu Bang's attack!