The Netherworld Ghost Realm is so big, let alone three people, as long as you want to hide, even if there are three thousand people scattered in all corners, no one will know.

Lu Yan and the others are hidden in a vast mountain, although this mountain peak is magnificent, but there is no dragon vein underground, so the aura is thin, except for some weak demon beasts, there are few human tracks, which is why the three of them chose to heal here.

I didn't expect them to sit in the belly of the mountain for a year.

After a year, the injuries suffered by the three of them have all been cleared, and their strength has made great progress, of course, all the spirit stones and pills have also bottomed out.

The Shui Yun Battle Armor's machine spirit also woke up after they finished their cultivation and appeared in front of the three of them.

Monk Dongming was so frightened that he almost didn't jump up, of course he could see that the other party was just a machine spirit, but what kind of grade the artifact that could appear in the form of a soul was simply unimaginable.

Especially the fluctuation of his divine consciousness from his demigod weapon, the Vajra Demon Suppression Pestle, it was a complete shock, and it was the fear of the lower artifact of the superior artifact.

Lu Yan didn't explain but smiled mysteriously, of course Monk Dongming wouldn't ask boringly, but he always kept a distance from him, and he seemed quite jealous.

Then they walked over the mountain and flew towards the center of the Netherworld.

To open the Nether Vault, you need not only five keys, but also an altar.

And the altar is in the ancient city!

The ancient city is the oldest old city in the Netherworld Ghost Realm, and its origin is no longer verifiable, and according to legend, this is the place of origin of the ghost clan.

The ancient city is surrounded by many mountains and ancient veins, these lofty mountains and mountains are incomparably ancient, not only full of aura, but also exude the taste of historical wilderness, which is simply a blessed land of immortals. It's as if every mountain is a dragon vein.

However, no force dared to establish a sect here, otherwise it would inevitably be ominous.

It is rumored that ten thousand years ago, there was a top force called the Sunrise Dynasty who did not believe in evil, but built the palace on the oldest mountain, and the entire Netherworld was in an uproar.

But when the entire dynasty moved over, everyone died silently overnight, and even some of the ancestors of the Nine Great Perfections of the Human Realm also died without a problem.

This shocked the entire Netherworld Realm, and since then, no force has dared to attack that mountain range.

But the ancient city seems to have existed forever and is not affected in any way.

The years are merciless, and the mountains and rivers change, just like all walks of life. The various forces in the Netherworld have also risen and fallen, some mountains have become ruins, some rivers have broken off, some have sunk the earth, and some mountains are now in the middle of the city.

Once a huge family, a Taoist system that has been inherited for countless years, it is difficult to withstand the baptism of the years, and finally disappears and turns into ruins. But the ancient city has remained unchanged from ancient times to the present day.

When Lu Yan and the others crossed the mountains, they saw a vast plain, an ancient city rising from the ground, and the mottled city walls were written with the taste of history. Even the grass and trees in the city seem to tell the history of the past.

They did not enter the ancient city, because the altar was thousands of feet away directly in front of the ancient city gates.

The altar is not large, but it gives people a sense of grandeur. It is in the shape of a five-pointed star, simple and simple, and is made of strange soil of five colors. It is full of the breath of time, and I don't know how many thousands of years it has existed.

There was once more than one force that was most interested in this altar, but it couldn't destroy it in the slightest, even if the power of the Nine Great Perfections of the Human Realm came with the artifact of the foundation, but it still couldn't help it, and it was even attacked by a strong backlash.

Since then, no one has bothered with it.

The ancient altar was engraved with intricate runes whose meaning no one could read.

Of the five keys, Lu Yan and Ye Qinglan each have two, and Monk Dongming only has one, of course he doesn't have any opinions, you must know that Lu Yan has helped a lot to get this key.

Moreover, the method of opening the Netherworld Secret Vault was also taught by the instrument spirit of the Water Cloud Battle Armor.

The three of them looked at each other, and a drop of essence blood dripped into the leaf-like key, and then tossed it onto the altar.

Suddenly, the five-colored light shone brightly, the five keys suddenly became crystal clear, and the runes engraved on the altar all shimmered, and the entire altar flowed out of a soft light.

"Click, click, click......"

The sound of shattering came out, and those runes rushed out one after another, as if they had life, and all of them rushed out and appeared in the void.

"Boom......"

The glowing runes in mid-air condensed together, and gradually formed a huge gossip, and a mysterious force vibrated out.

It is a shocking picture, and those ancient characters and symbols have incredible power, condensed together and manifested into a huge gossip diagram, which hangs over the altar.

And this is just the beginning, and then, I saw a Taiji diagram emerging in the center of the Bagua diagram in mid-air, and two yin and yang fish hugged each other.

Around the huge Tai Chi Tai Bagua diagram, the space was distorted, the light was misty, and the Bagua symbols corresponding to Qian, Kun, Xun, Dui, Gen, Zhen, Li, and Kan shone after another, like a set of mysterious and ancient passwords shining.

The two yin and yang fish in the Taiji diagram are like two strange portals, constantly vibrating, slowly opening a gap, as if connected to an unknown existence.

The brilliance continued to shine, and the eight symbols of the gossip were flickering and flickering, and finally after changing many times in a complicated order, they finally all lit up at the same time, emitting a dazzling light.

"Boom!"

With a dull vibration, the two yin and yang fish in the center of the Tai Chi Bagua diagram slowly opened, and in the process, there were stars shining from time to time, the sun and the moon rising and falling, and there was also full of vitality and lifelessness, which seemed to be all-encompassing.

In the end, the Yin Yang Fish is really like a portal that completely opens.

Immediately after, Lu Yan and the others saw a dazzling light gushing out from the portal, stabbing people so that they couldn't open their eyes, and even their spiritual sense couldn't detect what was shrouded in the light. The entire earth also shook violently, as if the sky was about to collapse, and the five-colored divine light that rushed into the sky penetrated the heavens and the earth.

When all the brilliance dissipated, where could you still see the shadow of the five-colored altar, only to see a giant tree standing there, the stars lingering, and the sun and moon coming out of it.

This tree gives people a special feeling, when they see it, they feel that it is the largest giant tree in the world! It gives people the illusion that this giant tree can hold up the sky and cover the earth!

"World Tree!" Lu Yan couldn't help but be moved when he saw this giant tree, and muttered. (To be continued......)