Naku and Lumina ran without looking back deeper into the forest, they both then stopped right on the beach.

"Haah...hah...sea...? what is this place?" Naku breathlessly asked.

"Huff... this is the sea that shows the border between human territory and the dark historical war area, the war between angels and demons." Lumina said as she walked towards the ship that was anchored and hidden behind the rocks.

"Is this your ship?" Naku said as he followed Lumina onto the ship.

"This is the ship that Sis Luna prepared before she left to do something important." Lumina looked around and pulled the anchor.

"That means she's still here...? Are you going to leave her?" Naku put down his bag which contained several books and Nano which was in sleep mode.

"It's okay, Sis Luna has her own way to go to the Underworld." Lumina smiled at Naku.

"Underworld? That's the location we're going to? I don't know anything about this world... because I have amnesia. I also didn't have time to read the book I bought in my bag. Can you explain to me a little about this world? You too just said this location is the border between humans and the battlefield of angels and demons?" Naku said while helping Lumina to prepare the sails of her ship.

"Well... then let's sail first, and I'll explain what I know." Lumina then channels mana into the crystal on the ship's steering wheel, instantly making the ship sail by itself.

"So... I will start from the great war between Angels and Demons." Lumina said and sat down on one of the chairs in the ship's rest room.

"So, in 1250... Angels and Demons started a great war and caused both sides to suffer huge losses, the war even destroyed many regions and even made the world's climate disorderly, and humans were trapped Between the wars of the two races." Lumina told Naku while drinking the tea she brewed.

"Race? Then are there other races besides humans, demons and angels?" Naku asked Lumina which made her look confused by Naku's words.

"Of course... because this world was originally ruled by 10 strong races, which was: Angels, Demons, Mutants, Elves, Dragons, Vampires, Abyss, Dark Beasts, Dwarves and Humans." Lumina said while looking at Naku who seemed to be observing her with high focus.

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"Then... these races must be separated by borders as you said?" Naku said.

"Yes, Demons, Mutants, Abyss, Dark Beasts, and Vampires are in the Outerworld... while Angels, Elves, Dwarves, and Humans are in the Coreworld. This world consists of 3 layers, the outermost layer is called the Absolute Core which protects all living creatures in it are protected from cosmic radiation and dangerous mana, while the second layer is the Outerworld, where this layer is a barren world dimension that does not have the slightest nature mana or it can also be called the Underworld because in this dimension the sky is below and the land is above , and for the Coreworld, which is the deepest and safest layer rich in nature mana and angelic protection to protect the races that are not banished by them." Lumina explains it to Naku.

"So... the banished race is not loved by Nature?" Naku asked Lumina.

"Actually... we have searched for the remnants of history left behind and discovered the fact that it was not Nature who banished them, but Angels make natures banished them... that's why the races in the underworld, especially the Demons hate angels because they banished them all to the Underworld." Lumina put down her tea and walked out of the room, Naku followed her and saw a few small islands full of rocks.

"Look, these are the remains of the darkest war in history... Dimensional War." Lumina said and showed Naku islands filled with rocks where the rocks were petrified angels and demons.

There are many dimensional cracks around the statues explaining the name of the war, and Naku sees an Angel stabbing a Demon but the Demon also stabs the Angel.

"..." Naku looked around observing him.

"We've arrived, get ready Naku, we will abandon the ship to enter the Underworld gate. Lumina took some of her things and stood at the edge of the ship.

In front of them there was a very large but motionless whirlpool, and in the middle of the whirlpool there was a white pillar with a pattern of small black squares around it. The atmosphere around the area was quiet and as if time had stopped. The pillar stood tall through the sky and there were even dimensional cracks around it which looked beautiful but also scary.

"We.. jump...?" Naku said looking at Lumina who was smiling.

"LET'S GO!" Lumina jumped and was followed behind by Naku.

They both touched the pillar and were absorbed instantly, Naku and Lumina seemed to have fallen into a calm ocean and all gravity rotated according to the rules of the Underworld dimension where the land was above and the sky below, Naku and Lumina fell freely in the sky while seeing millions of flying island with a city on top of it.

"THIS IS THE UNDERWORLD..?!" Naku shouted loudly for Lumina to hear.

"YES! ISN'T THE VIEW FROM UP HERE BEAUTIFUL?! OH YES WE'RE BASED ON OUTERWORLD RULES, WE'RE 10KM ABOVE THE SKY, SO LOOKING FOR A WAY SO THAT WE DON'T DIE ON THE IMPACT!" Lumina shouted at Naku who looked panicked hearing Lumina's words and she laughed at his reaction.

"WHY DIDN'T YOU TELL ME SINCE WE WERE ON THE SHIP?!" Naku screamed in panic seeing Lumina who was laughing.

"AHAHA! I'M SORRY! I LOVE SEEING THE REACTIONS OF PEOPLE WHO ARE ENTERING THE UNDERWORLD FOR THE FIRST TIME, I ALSO DON'T KNOW HOW TO LAND SAFELY OTHER THAN WITH SISTER LUNA!" Lumina laughed and Naku shook his bag to wake Nano.

"AAAAHHH!!!" Nano screamed because she was being shaken by Naku.

The three of them continued their free fall without any signs of slowing down towards the Underworld islands.