"Is this supposed to be a dungeon?" Styx disdainfully said in Therina's mind

The inside of the dungeon was a massive stone cave system with various carved block like structured jutting out of walls and the sporadic giant pillars between the ground and fifteen-meter ceiling. Stone mushrooms grew in damp crevices and fungus grew over walls and the ceiling.

Nonuniform light arrays were inscribed up high on the walls an pillars, shedding a dim light across the entire dungeon. Little care placed into the dungeon according to Styx's standards, to which his opinion ended up with "at least the floor is flat".

"It is. Also, there appears to be a higher mana density in the air. I can feel it prickling my skin."

"That means this dungeon is regenerating mana faster than I do! That's completely unfair! What is the cause behind it?"

"It could be related to the size of the dungeon."

"No, size has nothing to do with mana density. There is either a natural mana sink, or a vein of some sort of mana rich material feeding mana into the dungeon. It could also be some form of mana generation."

"Is it possible to create mana?"

"Not from nothing. But the way the energy in your mana network refracts into mana means it can be derived from life sources. It may be possible to tap into the planet's boundless ocean of lifeforce, or some other energy source, to effectively "create" mana.'

"I don't understand any of that."

"Of course you don't. I like to think of it as educating you."

Therina was feeling somewhat complicated at Styx's last remark, but she understood him well enough to know he wasn't intending to insult others. She loved him despite those aspects of his, although that was heavily called into question when she learned the origin of the 'point and click method'.

"Make sure you collect several large bags of the mushrooms and moss too."

"Yes. I will collect them on the final day to prevent them from dying before getting back."

Sounds of battle seemed to be getting closer as Therina walked through the dungeon under constant effect of her Concealment skill. She walked around one corner and found a party of four young adventurers fighting three kobolds – jackal headed monsters who moved and attacked quite quickly.

They appeared to have just reached adulthood and received their jobs. One of them tanked damage, while two others served as both vanguard and damage dealers, and the fourth was a female apprentice mage who served at a party leader and occasionally sending out fist sized compressed balls of sharp wind blades.

Therina was avoiding battles as much as she could to avoid reaching the level up requirement of experience before she saturated her mana network with potential.

The party took some minor damage, and the strap of the tank's shoulder pauldron had been cut and would no longer sit on his shoulder.As the kobold's died, they didn't leave corpses. They dissolved into ashes which evaporated in dark pin sized motes of light, leaving behind a fingernail sized mana crystal. Therina also had to collect a decent amount of mana crystals to both sell and bring back for Styx's research, but she was disinclined to snatch them from a party of fledgling adventurers.

Monsters in dungeons could be summoned at the expense of mana and were the traditional method for defending the dungeon by killing any intruders. As they were just mana constructs of the dungeon, anything killed by a summoned monster would provide all their experience to the dungeon too, which was one of the sole factors for dungeon breaks, unleashing a monster wave upon the world.

When one of these monsters died in the dungeon, ten percent of the experience given by the monster would go to the dungeon as well, further helping it grow.

Summoning arrays could be created as well, which every dungeon in the world relied on to produce the maximum number of monsters. These arrays would absorb and store up ambient mana and summon the monster programmed into the array whenever the stored mana was sufficient. This provided a steady stream of monsters without relying on the dungeon's own mana.

When they died however, they didn't leave physical bodies or materials behind, breaking back down into mana. What they left instead was a stone of crystalized mana, with monsters built with larger amounts of mana leaving behind larger, purer crystals.

This setup has been taken advantage of by civilizations from further back than the oldest history records.

Kingdoms take over dungeon cores and build cities around them. Without any traps or unexpected monsters, these dungeons become their most valuable assets as they are used to provide experience to train soldiers in mass, endless mana crystals and other minable materials.

They were open to the public as well as any monster killed would return experience to the dungeon core itself which was under direct control of the city lords.

Dungeon cores often had flaws though, such a certain functions they could not do that others could. They were then graded from A to H depending on the number of flaws. There were also S, SS, and SSS special grades outside of the standard ones for cores with rare and unique functions, although that didn't necessarily mean they were stronger or were without flaws.

Authentic dungeon core grades could only be assigned by a representative from the world wide conglomerate Dungeon Traders though, as they were the ones who created the criteria and a certificate of grading was the sole guarantee of a dungeon core's quality.

The fact that Styx had a flaw that made him unable to summon monsters was an endless source of grief to him, which he frequently complained about.

~~~~~

Therina finished exploring most of the dungeon's first floor in several hours. The sheer size of it was enormous, but there were maps on certain walls indicating where a person was and nearby safe zones.

The entire floor was filled with kobolds, goblins and carnivorous rats, enough to challenge low levelled people, but only gave poor amounts of experience.

The stairs down to the next level were back at the beginning.

This dungeon had ten floors in total. All the floors were relatively the same with some changes in design and color to help people differentiate, but they were aimed at being as efficient as possible for the purpose of a dungeon belonging to the kingdom.

There were also open veins of ore in some of the floors, which people were free to mine for their own usage or selling. The earth had endless amounts of raw ores that the city lord could control the dungeon to mine without having to worry about others mining it too. If he was to stop them from doing so, it would only serve to harm the economy of the city.

On the fourth floor, Therina was confronted by an ogre easily twice her height and wielding a giant iron studded wooden club."Grooarrrr!!"

The ogre screamed as it swung its club down on top of her head.

Therina was fully alert and in battle mode. She deftly dodged to the side of the club while simultaneously drawing her manasteel sword.

The club smashed onto the stone ground with a large collision, blowing dust everywhere but miraculously causing little to no damage to the floor. Seeing her dodge to the side, the ogre swung its free hand down at the elf to club her to death.

Ogres were known for their stone like skin and brutish strength, and getting hit by its fist would at least cause heavy damage the Therina.

She wasn't about to let the ogre hit her into the ground though. She slipped under its club-wielding arm and slashed her sword across its wrist in one fluid motion.

The ogre's skin wasn't to be underestimated, as her sword was met with fierce resistance and only cut half as deep as she intended it to.

The ogre roared again, this time in pain as it pulled its hand back, still with enough strength to hold the club as the tendons weren't severed.

"Miss elf, it looks like you need some help!" A voice called out from behind her as a group of three men approached her, two sword wielders and an archer.

"Stay away," Therina coldly stated with a glare before focusing on the ogre.

The men had sleezy expressions as they watched her fight the ogre. She danced around the ogre's attacks and continuously slashed and stabbed its vital points.

She backflipped over a sweeping attack by the ogre and at the same time, pulled out one of her steel throwing knives. As she landed, she flicked her wrist and the throwing knife launched in a grey streak. The ogre cried out in pain as the throwing knife stabbed deep into its right eye, blinding it and clouding its mind with pain.

"GROAARRR!!" The ogre screamed as it entered a berserk state and tried to violently smash the small elf in front of it while disregarding any damage it took.

"Do not take your focus away from those three humans," Styx warned in Therina's mind.

She naturally hated humans and was constantly waiting for a chance to attack them. She had actually been leading herself and the ogre closer to them, hoping to slit their throats before they can respond.

The ogre just blindly charged at her now and was on the verge of death.

The three humans who had been watching had sinister expressions on their faces. Not only was it an easy target to kill steal, they were deeply infatuated with the elf's beauty and wanted to have their way with her.

Therina was just a lone elf, so the archer took the initiative and drew his bow while her attention was on the ogre.

He was a <Lv. 15> Apprentice Huntsman, and used the archery skill Snipe, which launches an arrow propelled by mana, causing it to fly two to three times faster than a normal arrow.

The timing of the attack was immediately after Styx warned Therina, almost as if he jinxed her by saying it. She had in fact been constantly keeping them at the side of her awareness so when she saw and felt the ill intent along with gathering mass of mana behind her, she knew they were attacking.

At the same time as the arrow was shot, Therina spun around and raised her sword to block it with the flat of the blade. Reinforced by her own mana, the blade suffered no damage, but she was still thrown off balance.

"Human scum," She said in the beautiful elvish language as her expression was covered in frost.