Why do Tanaka need to build a dungeon when he already have Aincrad? well, the thing is, Tanaka needed to know the scale of power of the mobs.
He doesnt know about a damn thing about the other monsters other than the Tailed Beasts, well, there is also the dog from Konoha but that is for another time.
The other reason is to appease the fans of Solo Leveling, there was a guild but where is the Dungeons?
Anyway, that is that, the place where the dungeon was placed on the underground just beneath the Floating Island.
Tanaka also used the Chakra portal to go there.
Stepping inside the underground, Tanaka was greeted by tons of caves, though they are not really mined, it was just a decoration.
Tanaka will use these caves as the entrance to the dungeon.
This place is called the Dungeon City.
Tanaka then stepped in front of the closest cave, he sat on lotus position and entered his landscape, he then molded his landscape the same as the Dungeon City, slowly his landscape had changed and was the same as the Dungeon City.
'A portal to an empty plane, the same as Virtual Reality World' Tanaka begun to imagine how it works, Tanaka had read many VR game elements novels and manga that he already had the gist of it, also added with his game making experience.
But what surprised Tanaka was his Chakra, it was getting sapped by the technique at a very fast rate, if not for his chakra being extremely huge, the same two tailed beasts chakra getting merged together.
Tanaka would have passed out in the middle of this technique, it already took 30% of his chakra and he was only halfway on finishing the 'virtual world' he was creating.
Creating a world is like doing a programming, Tanaka had to put correct codes or the laws of the portal, he needed to be precise because unlike in programming.
Once he made a mistake, everything needed to be redone from the very start, and Tanaka didnt want that, he had never liked the feeling of his chakra being low.
It took about an hour for Tanaka to finalize the dungeon portal, he then imagined, copy and pasting the portal to the cave in the real life.
*Dang!
A loud sound came when Tanaka pulled the portal from his dreamscape to the real life, it was like a metal clashing with another metal creating a sonic boom from their collision.
Tanaka didnt mind the sound and he felt exhausted, He only have about 30% of his chakra, surprisingly, the creation of the Dungeon Portal took 60% of his chakra and only 10% to pull it out of the dreamscape.
"Why does it feel another way around?" Tanaka thought, but he didnt mind it, it was probably how it works or the author was high and made such a huge mistake, anyway, he is also too lazy to change the settings of the skill.(Slowly fixes the wall)
Anyway, Tanaka didnt immediately entered the Dungeon portal but meditated, his Chakra recovery when meditating will increase the recovery of his chakra by 100%, he only rested for an hour before recovered 80% of his Chakra.
Tanaka then stepped inside the dungeon portal, or it could be called as Gate, As Tanaka stepped inside the Gate, what greeted him was a pure white empty space.
"Of course, I only made the portal!" Tanaka complained, but this was within his expectation, he didnt connect it to a different world or anything, he just made a portal.
Tanaka closed his eyes and entered his dreamscape, this time, his whole dreamscape turned pure white, as for the portal, he set it aside for now, it would be a pain to recreate it once again.
"Now, for the first dungeon" Tanaka focused himself, creating a small plane on the dungeon is like making levels in a game.
Tanaka just had to put the layout, the background, the monsters, environment, and the other elements.
First, need to make a plan on what world he would make, there are many dungeon games from his past life and some had amazing designs.
Then, a level came into Tanaka's mind, a long cave with low level monsters, it could be said it was only a D-rank dungeon, monsters are Goblins, there are many holes around the caves making it easy for the monsters to ambush the raiders.(I will name them raiders for now)
The Goblins carries either a wooden spear, a dagger coated with poison, they could also reproduce very fast which means their numbers are f*ck tons of them.
That was the 1st level, the 2nd level which is also the boss room could be found at the end of the cave.
A huge stone door that made it seemed like an abandoned temple, on the other side of the door was towering stone statues and a large statue sitting on a throne.
Most Solo Leveling Fans will know what dungeon is this, Tanaka also buffed the monsters in the dungeon since Shinobi's are already powerful to begin with.
Now, this dungeon has the Goblins cave from Goblin Slayer and Cartenon Temple which is the place where Jin Woo received his system.
After doing some finishing touches, Tanaka left the first finished dungeon, he now only needed the Chakra battery for it to start working.
Anyway, Tanaka moved to the second Dungeon after that and pasted the portal once again and created a new level in the dungeon.
Each dungeon only needed about 2 hours to finish and moving on, Tanaka spent 3 days in the dungeon without sleeping just to finish everything.
After 3 days, Tanaka left the Dungeon City as for the rest of the work, he will leave it to his trusted friends.
Once he got out, he was greeted by his assistant Erina with a smile, Tanaka also smiled back and put his arms around her shoulder and acted tired, he was sure she would dump all the papers he had left for 3 days if he acted he was fine.
Erina blushed a little bit but still supported Tanaka to his Castle, Tanaka then told her to make the Division which is responsible for the dungeon to start, he then asked for some matters while he was away.
"Yes, About two days ago, Kiri had announced the establishment of an organization called the Seven Ninja swordsmen of the mist, they are known to consist the greatest blade wielding Shinobi that Kirigakure could produce, from the intelligence we received, they wield weapons that Kiri had found from an ancient ruins" Erina reported.
"Kiri Swordsmen huh?" Tanaka nodded, he then suddenly smirked, then a boss music suddenly started to play in the background and god knows where it came from.
Erina sighed and knew what is coming, she immediately took out her notebook and pen.
"Hehe, if Kiri have an organization like that, why cant Ryu have one? Erina, we will also establish a group under Ryukage, I will call them, the Seven Deadly Sins, I will personally choose the members and give them Weapons of Sins, like the name said, there could only be seven, then while Im at it, I will also establish an assassin organization, Their main function is to handle reconnaissance and assassinations, they will be called the Nigh Raid, I will give you the list later" Tanaka said to Erina.
"As you wish" Erina nodded.
Tanaka wouldn't dare to do this before he learned the Creation of All Things Technique but now, he could do it, though he may have to do some experiment and research first.
"Any other news?" Tanaka asked.
"The other countries are starting to develop their armies, they are also starting to do hidden activities." Erina reported.
"I guess, even with my presence along with Madara and Hashirama, War would still happen, Is this the work of Zetsu?" Tanaka stood up and looked at the horizon.
His presence gave many changes to the Shinobi World, he prevented Madara and Hashirama from fighting each other to death, he ended the warring states period and he became one of the most powerful beings in the Shinobi World.
There had been many changes, but it seemed like someone is trying to put things on its rightful tracks, and Tanaka could mot think of anyone other than Zetsu.
Or maybe, there is someone else in the Shadows, manipulating everything.
But Tanaka didnt mind, everything are just getting interesting from here on.
The background music ends.
Tanaka then turned to Erina.
"We will also revise our School System, The old Academy will be changed and new schools will be built, It would be renamed as Hunters Academy, and the new schools will be Ryuotsuki Culinary Academy, Ryu Shinobi Academy, Ryu Demon Slayer Academy and Martial Arts Academy, That is all, you may leave" Tanaka listed.
"Yes" Erina bowed and left.
Tanaka and the author yawned and wanted to sleep.