Primrose phased into visibility as Callum walked towards the deceptively blank wall. He willed the Core Room door to appear and she raced ahead of him and through the still closed door; Callum had to physically open the door.
Once they were before the Castle Core itself, Primrose displayed the stats of the Castle as well as the map of the surrounding area.
"Do I have to add these Beast Cores one by one? Or can I add them all at once?" Callum questioned as he looked over the two displays.
"I'm afraid that they can only be added one by one," Primrose hesitantly said with a frown.
Callum sighed.
"I figured as much," Callum said as he opened his bag up and approached the pedestal and core, "So, is this the same process as merging fragments of Beast Cores? I just think 'merge'?"
"Yes, sir Callum, sir. Just place the Beast Core against the Castle Core and think merge, join, or something similar. The actual word isn't that important; intent is what really matters."
Callum began adding the Beast Cores' Mana to his Castle, the process soon became boring. The two orbs would gently pulse with a dim light before the Castle Core literally sucked in the other one in a brief instant.
The Castle Core had 1,630 Mana when he started, so he needed to add 19 Beast Cores in order to gather up enough Mana to upgrade Mana Siphon to the next level. He only had a handful of Beast Cores left when he was done.
As soon as he had the needed 3,500 Mana, Callum eagerly selected the upgrade; a little display popped up in his vision.
'Note, Mana Siphon upgrade in progress. Time Remaining until complete: 00:59:57.'
He had an hour to kill, so he went upstairs to his treasure chest and he started to transfer many of the valuables to his bag. The guard had reminded him that there were others around and his door, while sturdy, was not an insurmountable obstacle.
As he was stuffing things into his bag, he looked over at the fairy hovering in midair, "While I was being bound to the Castle Core, in my vision I saw a bunch of valuables stored inside the room. My stuff will be safe down there, right?"
"Mostly it will be, Lord Callum. It's as safe as your Core Room is, but most Master Class individuals might be able to breach the inherit protections of the Core Room; and a very few Advanced Class people, if of a high enough level and the right class, could also do the same."
'Still much safer than my room, just about anyone could break into my room if they really wanted to,' Callum thought to himself.
Callum accepted this news with a resigned expression as he finished loading up the bag with its first load; the bag wasn't full, but gold and silver were heavy and he didn't want the bag to burst open at the seams.
He had already been aware that some people could forcefully access his Castle Core if he wasn't careful. There had to be a reason why he could upgrade the defenses of the Core Room, he just wished he hadn't already spent the Mana on the first upgrade.
The first level of Traps was probably not going to bother any of those with the ability to find and breach his entrance, and he couldn't spare the Mana to upgrade Traps even further.
He dumped the coins out into one corner of a room and then went back up for a second load. This trip, he grabbed more coins, most of the precious stones, and the Uncommon Beast Cores, which had 500 Mana points.
He left behind a quarter of the coins, a couple of precious stones, and some of the Common Beast Cores that he had acquired. Most everyone probably knew of his treasure chest. If someone broke in trying to steal from him, they would get suspicious if they found nothing.
It was better to leave something for them to find instead of encouraging them to give his room a closer look.
_____
The timer still had a long way to go and he had already sorted his loose pile of valuables as best he could. He started to ponder what he had learned about dungeons today, before it occurred to him that Primrose might have additional insights.
"Primrose, some people were telling me about dungeons and that got me thinking. I was wondering if you had anything you could tell me about how Dungeon, Castle, or City Cores function and the relationship, if any, between them."
The fairy stopped dancing and twirling through the room and zipped over towards him.
"That's a very broad question and there is a lot to go over, sir Callum. I can give you a brief overview, but we'd be here for days if I answered that fully," she answered in a much more serious manner than her usual cheery self.
"That's fine, an overview is what I'm looking for, please educate me."
She grew to her largest size and he could easily make out her facial features; usually she was much too small for him to be able to make out the details of her face. Her dim yellow glow and tendency to dart around with her wings only complicated things further.
She had a contemplative look on her face and her eyes were narrowed in concentration.
"First, how much do you know about Mana? Have you ever heard about unrefined or refined Mana?" She easily read the look of confusion on his face and proceeded without giving him a chance to answer.
"Most don't care to know about the various Mana types, it's not knowledge that most people even know exists. Some stuffy academia types know, and of course a lot of owners of Castle or City Cores eventually ask."
"How do the two Mana types affect us? How about Castle Cores? There must be something if most owners eventually find out," Callum asked.
"It doesn't really impact other people much, or well it does, but someone could go their entire life without knowing, and not knowing has no bearing on their life," she explained.
"Unrefined Mana is constantly produced anywhere that two or more elements interact. A waterfall, a lightning strike, a volcano erupting, and waves crashing upon a beach all produce unrefined Mana."
"Even a tiny babbling brook produces an infinitesimally small amount of unrefined Mana. But the greatest producer is deep beneath your feet, the magma center of Terra. Unrefined Mana permeates everywhere, it seeps in with every breath you take or through your pores."
"That sounds a little weird, but it's not harmful, right?" Callum interrupted.
"It can be, but I'm getting to that. Now all living beings: plants, animals, monsters, and people take that unrefined Mana and change it into refined Mana. Higher level or the most sentient beings refine that Mana more efficiently."
"And that's where the danger comes in, because refined Mana can mutate living beings. If it's left uncontrolled, the mutations can be extremely painful and detrimental. And the more refined Mana inside of you, the greater the risk of a mutation occurring."
"Oh, oh gods! Am I in danger of mutating?" Callum interjected as he began to study his body for a hint of a mutation. He was just about to start using up all of his Mana when Primrose interrupted him.
"No, you're not in danger. At least not right now, please calm down. The gods saw how harmful this was after the random mutations started to happen. Most of them worked together to come up with a solution, so you're safe," she soothed.
"Anyway, like I was saying," she continued when Callum visibly calmed down, "If left uncontrolled, those mutations can produce monsters. It's how they first came into being in the distant past, before the gods stepped in."
Callum shuddered at the thought of the Mana inside of him mutating him into a slavering monster. It was not a pretty thought.
"The gods came up with a system to harness that Mana productively without harming the individuals. They created the leveling system, complete with classes, spells, and abilities. In this manner, you can safely guide how the Mana mutates you," Primrose finished.
Callum was stumped. He had been afraid of mutating, but according to Primrose, he had already mutated multiple times in his life.
"So, I was actually mutating every time I added points to my attributes or gained a new ability? What about the Mana in my Mana pool, is that a danger to me?" Callum questioned.
"Yes, mutated, but in a controlled manner. Your Mana pool safely stores some of your refined Mana, but the majority is stored away as XP; XP is the amount of refined Mana inside of you that's been set aside for your next level up."
Callum nodded at this latest bit of information. Today was a day of shocking revelations, and he was feeling overwhelmed.
"Now living beings aren't perfect vessels and refined Mana seeps out into the world at large, left unchecked, that Mana would eventually start changing the very fabric of this world," she stated and Callum absently nodded along; he was still trying to parse everything.
"So the gods experimented. They created or modified elementals and other beings so they could use the latent Mana in the world. Another line of experiments led to the creation of something else that could process Mana; thereby creating Dungeon, Castle, and City Cores."
"The gods created this?" Callum pointed at the Castle Core before him.
"The first ones, yes, I'm not sure if this one was created by the gods or not. Dungeon Cores proved to be the most efficient at doing what the gods wanted, so they made it so Dungeon Cores form naturally," she clarified.
Callum was about to ask a follow up question, when he received a notification that the upgrade had finally finished. He eagerly opened up the notification to see the results.