As Natsu realized that Rias was a fully sentient being, his determination to never lose her further grew.
"Rias?"
"Yes... Darling?"
Enjoying how cute and newly married wife Rias was sounding, Natsu unconsciously grinned.
"Tell me all you know about the DH System."
Smiling as if she appreciated the question, Rias said, "The DH System, also known as the Dungeon and Haven System, is a completely omnipotent system which governs the whole universe in its rules and regulations."
"The DH System has been in existence for a very long time, and every planet depending on its population and technological advancement are automatically selected and seen if they are qualified to be a part of its area of influence."
"If they are, the DH System will officially take control of the planet and start directing its development in the way it chooses fit."
As he listened to Rias, Natsu noticed that Rias did not show any signs of having reverence or worship towards the DH System.
This pleased Natsu greatly, because he wanted Rias to care for him, and only him.
"The planets selected by the DH System will officially be introduced on the path of evolution using monsters and death as a catalyst to achieve them."
Hearing her Natsu nodded his head and further asked, "Tell me about Dungeons and Havens."
As expected the response from Rias proved his thoughts about Dungeons and Havens to be true.
Dungeons were controlled by a Dungeon Master who would try to kill the intruders with the creatures inside it. The more people died inside a Dungeon, the faster it would grow bigger and more dangerous.
Havens were places which provided security for the residents of the planet from all the monsters which arrived due to the DH System.
And finally, the common element between Dungeons and Havens, it was the adventurers.
Not every human needed to become an adventurer, but becoming one was the only way to grow stronger, and possibly achieve limitless strength and immortality!
The only reason to do that however, was by entering a Dungeon and killing the monsters inside it.
On the other hand, no one would grow strong by killing any number of the beasts which infested the planet, or fellow humans inside or outside the Dungeon.
Having grasped more or less of the basics, Natsu began to question about more complicated things, some which even Rias didn't know the answer to.
Because it seemed that she wasn't completely omnipotent, and the knowledge she had depended on Natsu, and his Dungeon Master profession's level.
Luckily she did know the answer to a few questions which were vital to Natsu, like what was a dungeon core.
The answer to that was, Rias showing him a small black cube which seemed like the miniature version of the cube he touched to make Rias.
It seemed that when the small cube was destroyed, the particular dungeon would get destroyed. And if another dungeon master touched it, they could choose to conquer it and make it their own.
At least knowing that Rias wouldn't be harmed allowed Natsu to sigh in relief, as he started planning on how to keep the cube safe.
Unfortunately, just like he expected, Natsu couldn't take the cube outside the dungeon with him, and hide it somewhere far away.
Also, for some reason the cube couldn't be hidden in the walls or after digging a hole, because regardless of where it was, the cube would always be levitating so as to let everyone who sees know what it is.
This was also when Rias explained that she was only an interface between him and his dungeons, and could therefore not enter any area which wasn't his dungeon.
But, in case Natsu possessed multiple dungeons, she could easily teleport and appear in any of them.
Nodding his head from all the influx of information, Natsu moved his head further closer to Rias's waist which made her shyly squirm.
"Darling... This is very embarrassing... "
"Really? But I quite like this. In fact, I'm enjoying this very much."
Listening to Natsu, Rias blushed even more while feeling happy at the same time.
"Rias, tell me more about a Dungeon in detail."
Pausing for a while to collect all of her thoughts, Rias said, "A Dungeon like I said before is a place which the Dungeon Master fills with various species that he bought with DP to kill the intruders who in turn give him DP depending on their strength."
"DP means, Dungeon Points, darling. Since you are a Dungeon Master, you use DP to buy anything from the DH System for the Dungeon or your personal needs."
Thinking that the dungeon more or less worked the same way he expected, Natsu asked, "How much DP do I have now, Rias?"
"Before I can answer your question, you need to give this Dungeon a name, and create your Personal Guard."
"A name for the dungeon..."
Turning his head from the side to look up at Rias's face, or at least what was visible after her huge breasts filled his field of vision.
Natsu asked for Rias's opinion.
"Do you have any ideas, Rias?"
Thinking for a while Rias suggested what she felt was the best way to name a Dungeon.
"Since you can't relocate a Dungeon, I suggest you name the Dungeon based on its location."
"Based on the location... Okay! I'll name this dungeon, The Great Tokyo Dungeon!"
[The Dungeon's name has been set as The Great Tokyo Dungeon.]
[All of the Dungeon's features are now accessible to you.]