There are fourteen base affinities of magic, formed up into pairs of opposites; fire and ice, earth and air, water and lightning, light and darkness, life and death, body and soul, space and time. Each affinity embodies a concept, and is not limited to a single physical form. For example, a better name for fire and ice might be hot and cold. Fire and ice are simply the common visualisation of these concepts, adopted so widely that the nomenclature has been picked up by the System. Likewise earth and air embody solid and gaseous. Water and lightning are more nuanced, and could be described as matter and energy, or permanent and transient. An individual may be attuned to multiple affinities, but never to both sides of a pair: One may wield fire and earth, but never fire and ice. There are correlations; wielding fire and air is more common than fire and earth, as is light and life.

- Introduction to magic, from first year academy teaching materials

"System, how many floors do I have?"

Error: Floors exist that are unregistered. Registering 5 additional floors.
Error: Floors exist below core level. Core must be placed on the lowest floor. Relocating core.
Floors: 15 (effective floor increased by 5 due to excess external ambient mana)

Erryn basked for a while as it got used to the increased ambient mana, pondering its next move. The only thing on its list it could do immediately was to construct new floors, and find the upper limits of its new light element slimes. What it wanted to do most was to find some way to expand its reach on the surface, but there wasn't a sure fire answer to that. More floors could help, which was even more reason to start there.

Erryn started to dig out further floors, and placed dungeon vines and slimes. Floor seventeen showed the first change. Upon placing slimes into a room, the vines began to twist and the fruiting berries withered and fell off. Oddly, the vines were not trying to get away from the blinding light, but to get closer to it. The outer layer of the vines cracked and shrivelled back, revealing smooth green crystal beneath. The vines fruited, replacing the original berries with tight bunches of white crystals.

New flora unlocked: Crystal vine
Incongruity detected: Flora unlocked prior to unlock of flora category. Resolving conflict. Unlocking flora category. Unlocking basic flora.
New flora unlocked: Dungeon vine
New loot unlocked: Crystal berry
New flora unlocked: wheat, potato, corn, grape vine and 13 additional types
New monster unlocked: Lumenfang

A whole new category, and a lot of different varieties for it. All edible, and for some reason in a different notification to the dungeon vine. It only took Erryn a couple of seconds to work it out; the list matched that of the seeds and foodstuffs it uncovered in the vault. Why had the category not unlocked when Erryn had produced the first dungeon vine? Then again, the materials category hadn't unlocked due to regular dungeon stone either. Maybe it needed two entries before it kicked in. There was also a new monster, for some reason. That didn't seem related to the plant life and a quick glance around showed that Zephyr had switched species, apparently taking longer to change than the slime. Or maybe something to do with the flora had let him change?

Erryn planted some experimental crops across several floors; outdoors wouldn't work with the blocked sun, but too deep into the dungeon risked side effects from the ambient mana. Not that that would be a bad thing; it might unlock something else interesting. By planting on multiple floors, Erryn hoped to get some good crops, and see the effects of mana. Unfortunately, the crops were a complete failure on all floors. When Erryn placed them they did start to grow, but wilted and died long before reaching full size. It seemed that the System controlled rapid growth did nothing to obviate the need for water, which Erryn currently did not have.

With the food crops unavailable for now, Erryn continued digging out new floors. The very next floor gave the next surprise, the dungeon walls creaking as the stone changed. Erryn assumed it had reached the depth required for reinforced dungeon stone to spontaneously form, but seeing a patch of stone that had finished conversion, Erryn could see this was something else.

New material unlocked: Sun-plate stone

The material was blue with veins of yellow. It seemed that even the dungeon stone was affected by the light affinity. With nothing immediate to do with the new material, Erryn kept digging. Floor nineteen gave nothing new, but floor twenty was a total failure; the slimes could not be merged further, and any attempt to force it destroyed them. Erryn blocked off the twentieth floor to avoid any possible problems from having a floor with insufficient mana circulation, and registered the other four floors. "System, how many floors do I have?"

Error: Floors exist that are unregistered. Registering 4 additional floors.
Error: Floors exist below core level. Core must be placed on the lowest floor. Relocating core.
Floors: 19 (effective floor increased by 5 due to excess external ambient mana)

With the core relocated and even denser mana to play with, Erryn decided to practise its control over mana in the hopes of unlocking new skills that would permit it to continue its surface expansion. With careful inspection it found that it could tell apart the differing flows of light affinity mana from the original pure mana. Teasing the two apart was harder, but after a few days of trying Erryn succeeded. Creating basic dungeon stone, Erryn pushed on it gently with pure mana to create compressed dungeon stone, harder to create reinforced dungeon stone, and with light affinity mana to create sun-plate stone. Trying to reach another new tier Erryn pushed harder still, but failed to find anything new.

Reaching the limits of stone, Erryn experimented with other materials instead. Mythril nuggets still could not be afforded directly, so Erryn created some from silver to play with. Erryn flooded every available metal with both types of mana. Copper remained a disappointment, being transparent to both types. Silver formed mythril from pure mana, but while it absorbed light affinity it was not changed by it, melting once it became saturated. Gold hungrily absorbed both types, behaving in the same way as silver, but Erryn was still unable to fully saturate it. It could however tell that it was getting close. Platinum was identical, but needed even more mana to reach saturation than gold did. Like the precious metals mythril absorbed mana, but unlike them it did not leak it. Erryn was able to fully saturate the mythril despite it being just as hungry as platinum, after which it became opaque to mana without showing any further changes. Erryn could pull mana back out, but it was difficult, the mythril binding it tightly. A mythril nugget charged with light mana glowed brightly, despite the mana not leaking. Erryn had read about enchanted items but had no idea as to how they were made. Now it seemed to have accidentally created an enchanted torch. Going back to the platinum, Erryn watched the summoning of nuggets then manually replicated the process as it had done for other materials previously.

New material unlocked: Platinum

Iron proved interesting. It didn't absorb mana but instead, like the stone, was opaque to it. Unlike the stone, compressing iron with mana caused it to shatter in a rather spectacular fashion. Erryn was thankful that it had started with lower mana concentrations, and thus the experiment had taken place on a higher floor rather than in the core room like so many others. Erryn built a new empty room on the nineteenth floor to conduct the high mana experiments, whilst absorbing shards of iron that were deeply embedded into the walls of the room. Steel was also opaque to mana, but compressing it resulted in no explosions. It behaved far more like the stone, producing new materials and responding differently to different types and concentrations of mana.

New material unlocked: Mana infused steel
New material unlocked: Mana reinforced steel
New material unlocked: Glowing steel

The steel did require a somewhat higher mana concentration than dungeon stone, the ambient mana on the lowest floor still not sufficient to convert an ingot of steel to glowing steel naturally. Returning attention to the surface, Erryn practised manual summoning of both glowing and giant slimes. With the boost of the nine additional floors, Erryn managed to succeed with both. The light affinity variants were certainly more complex, but with further practise Erryn also managed manual summoning of shining slimes.

Turning its attentions to the edge of its territory, Erryn attempted to grasp the mana that lay beyond its reach. It tried to take more territory. Not the near automatic assimilation it had conducted previously, but fighting hard for every metre. Each time its attention wavered the mana snapped back, reversing its progress. Still Erryn persevered, determined to explore more of the world. Perseverance that was rewarded.

New skill unlocked: [Mana Control]. Your control over mana and your perception of it continues to improve. Inferior skills [Mana Finesse], [Improved Mana Manipulation] and [Improved Mana Perception] absorbed into [Mana Control].

Erryn's tenuous grasp over the remote mana suddenly solidified. It could see the mana settle into the ground, could watch as 'stone' became 'Erryn'. Everything was clearer, as if the world had snapped into focus. Erryn immediately began to expand its surface territory again in earnest. It could already tell that the cloud penetrating mountain was now within its range. From the maps in the vault it also knew that it could reach a few more towns and one major city. Also of interest was an inland lake. While the rivers flowing from it had dried up, Erryn was interested in the state of the lake itself. But it would take time to reach any of these locations, time that Erryn did not intend to waste.

Erryn placed chunks of dungeon stone, steel and gold in the experimental area of the lowest floor. The ambient mana hadn't changed, but Erryn could now grasp more of it, and push it harder. Starting with the stone, Erryn pushed against it with pure mana. The stone creaked and shrunk, lightening as it converted first to compressed dungeon stone, followed by reinforced dungeon stone, but then it shrunk again and darkened to an ash grey. Veins grew along the surface, but Erryn could see that unlike the sun-plate stone, they also formed in the interior. The veins pulsed with a dull blue light. Repeating with light affinity mana produced a similar material but pure white in colour, with the veins brightly glowing.

New material unlocked: Dungeon flesh
New material unlocked: Glowing dungeon flesh

Describing it as 'flesh' rather than 'stone' was strange. It wasn't soft and squidgy in the slightest; it was harder even than steel. But in the context of what a dungeon was, Erryn guessed it made a kind of sense. A body of stone, with veins of mana instead of blood. Repeating the process on steel unlocked nothing new. Erryn still couldn't flood a nugget of platinum with mana at a rate sufficient to saturate it either. Gold, on the other hand, finally met with success.

New loot unlocked: Orichalcum nugget
Incongruity detected: Orichalcum materials not available for purchase until dungeon has one hundred floors. Resolving conflict... Lowering purchase requirements impossible due to creation of further conflicts. Locking feature impossible due to feature already existing in dungeon.
Error: Unable to resolve conflict. Dungeon already designated as [Errant]. No further action taken.

Well there went the good behaviour timer. As expected. Erryn knew it was going to keep stepping over the edge of what the System considered acceptable, and really didn't care. On the other hand, it never had known why it had originally gone errant. This suggested that it could have been the unlock of mythril that had done it. Then the method of resolving this conflict in order to lose the errant tag would be to grow to one hundred floors, unless Erryn could convince the System to re-lock orichalcum. That would take... some time. Orichalcum responded to mana in much the same way as mythril, storing it up without leaking. Also like mythril, the nugget was too expensive to summon via the System, and so Erryn could not unlock it as a material.

With material experimentation complete, Erryn turned its attention towards its core. The previous attempt at manipulating its own core had been a qualified success at best, but now Erryn had additional skills available and greater understanding. It applied its improved perception as it spent mana and allowed it to regenerate, observing how mana flowed into the core and how and where it was stored. The observations made Erryn confident that it could try and enhance the core with very little risk; that it would have a chance to back off before things went too badly wrong. Erryn gathered the ambient mana in its core room, and after a moments hesitation, let it gently spill into the core.