Goblin Cave threaded its final corridors up towards the surface.

Surrounding its initial five floors — a series of dank, grimy caves laid out in linear switchbacks — was a twisting labyrinth of stark geometric chambers. It had limited itself to only simple materials for the final ascent, concerned that any of the more exotic materials could be detected through the ground. Consequently, the rooms were mostly blue-black glass, murkily translucent for a few inches, revealing in hazy shadow the faceted manastone wall behind it.

The layout was intensely dense: nearly all the granite had been replaced with its structure, with no unused chunks. It had corridors overlooking chambers, zig-zagging stairs forking off into jagged defiles, with lights from higher levels shining down. Rectangular pillars outlined massive open chambers, with perfectly square entrances opening at fixed intervals up their walls, providing no easy way up or down. All together, Goblin Cave considered the topmost five floors to be a single combined floor; there was no meaningful distinction to be made between its layers.

However, unlike its prior experiments, the chaotic exploration that had informed its expansions of its lower floors, every chamber and pathway in its upper floors was designed that way for a reason. The entire structure was a mana resonator, forming a warped, twisting current of mana that constantly cycled throughout its structure, half-isolated and half-overlapping with its own mana network. It was... ultimately it was a pointless trick; it hadn't got any closer to spinning mana threads or creating a fully isolated mana system. But its upmost floors were a massive mana bellows, formed out of mundane materials with only the barest slivers of manacrystal and serpent obsidian in focal cavities. It had done it to show off that it could do it, nothing more.

Goblin Cave had no idea how adventurers would take it. It was entirely possibly they wouldn't care at all about its artistry; it was prepared for that. They certainly hadn't seemed to care about anything else it had done.

More time had passed while it had dug out its final floors.

Its [Ascended Mana Goblin] had recovered, earlier than it had anticipated. Goblin Cave still didn't know if its weakness after its ascension had been due to a too-small soul, its autonomous nature, or any one of dozens of other hypotheses it had thought up in the mean time. The goblin had taken to delving its sub-dungeon — now with an obnoxious 12 sub-floor layout — with vigor, using its upgraded abilities to burn mana puppets into nothingness and harvest yet more glowing gewgaws. Goblin Cave was still waiting to pull the trigger on its next evolution; it wanted to try another test. It had marked the goblin it was going to evolve into an [Infused Amalgam] and had commanded its goblin-god to fill it with soul until it reached the same size as the ascended goblin. This may reveal if it was lack of soul that lead to the ascended goblin's infirmity. But Goblin Cave had another consideration, too: by every metric the system gave it, these goblins had an absurd glut of soul. But even that absurd glut seemed barely capable of animating them to autonomy. It had been trying to reframe its thought: it was not, as such, that the animated goblins were 'over-souled'. Perhaps it was that the soul quantum the system revealed to it was very small. A single unit of soul could be so miniscule it was at the very edge of being nothing at all.

Goblin Cave had seen plenty of soul dynamics operating with single units of soul. What it had not seen was the other end of the scale: if there was such a thing as too much soul, or if there were more involved dynamics that only revealed themselves at absolutely staggering soul thresholds.

This was where the goblin's reproductive rate was working against it. It had instructed its goblin-god to portion excess soul into the goblins' eggs, keeping those to be spawned, and to terminate the rest. But there were always, always more eggs. Given the number of eggs in a clutch (dozens), and the frequency at which the goblins produced them (constantly), there was no way for it to ever have an excess amount of soul free to let it build and build up. Instead, it had mostly been maintaining the goblin souls at the size it had originally spawned them — tier 36. But that had been and still was an accident of birth, with no meaning behind it.

The numbers worked out as such: the rate of goblin soul development was an outstanding 3.95% per month. This would lead to a soul doubling in size over the source of roughly 19 months if the rate remained constant, which was no means certain. As that growth was instead reapportioned to birth new goblins, this lead to the overall population doubling every 19 months. Death only slightly impacted the calculations, since the reaped soul was rapidly reinvested in the next clutch of goblin eggs. This formed a classic exponential curve. In practice, there would be limiting factors; every exponential curve was the lower half of a logistic curve which eventually flattened out. Presumably at some point the limiting factor would be the time it took goblins to grow to maturity and begin producing additional eggs. Physical space in the caverns would eventually be an issue.

But currently, they were on the ramp-up: after a several month delay to grow its ascended goblin's soul, a new goblin was successfully birthed once every other month (for sixteen months), then once a month (for another sixteen months), then two a month (for four months now). Its original collection of fourteen, making a motley encampment in a fungal grove, had grown into a tribe of fifty-two, forming a sprawling den within a half-cultivated fungal forest. They ranged all throughout the sprawling caverns of floor 50, squawking and squabbling. One pressure Goblin Cave hadn't anticipated was whatever maximum size a goblin tribe could be and still be stable: there had been more fighting between goblins, and an unusually high number of deaths from intergroup conflict.

Presumably — an intuition constructed from the many system descriptions of goblin types it had read over its life — the tribe needed a leader after some point in order to structure and enforce the power hierarchy, and none of the goblins so far filled that void. Its reincarnated goblin was still mostly insensate, and although it had been showing signs of more active interaction it was in no condition to act as a ruler. Its ascended goblin was more interested in delving than leading the goblins, although it had formed something of a clique with a handful of the other delving goblins. Those were the two most powerful goblins, and although there were others that seemed to be expressing more than the crude animal cunning Goblin Cave had grown to expect from its goblins, ultimately here as it seemed everywhere else, power was what mattered. There was a fungal farmer that had devised an intricate irrigation system for its swampy fields, mostly out of laziness of manually moving water around, but — it was level 2, and in any fight it would be the loser.

All that was to say, the goblin situation was evolving according to plan, and it would be, if the curve stayed on track with its projections, another twenty six months before it would consider leveling off the population growth and investing heavily in building up soul within each goblin. Consequently, its spawn templates were still depleted. It had some measure of success with its mana puppets: a few had managed to kill enough goblins to open up some simple evolutions, and here, where it wasn't constrained by the need for soul, it was able to more freely evolve its mindless puppets.

Invisible Servant construct (tier 2, unaligned)

A non-combat semi-corporeal shade mostly summoned to act as a menial servant. It cannot be seen, heard, smelled, or tasted, but it has a humanoid body-form capable of physical interaction. It is capable of obeying simple orders when left to its own devices.

Manaflame Guardian construct (tier 3, fire)

A flame wisp that has evolved to subsist on pure mana, giving its flame a fierce blue-white glow, but robbing it of its capacity to burn. Instead, it deals damage directly to its opponent's mana stocks, leaving lingering manaburn.

Mana Elemental construct (tier 3, unaligned)

A simple elemental from the plane of pure mana, bound to this realm with the glyph of imprisoning. A clockwork creature of precise action, it characterizes the most common aspect of mana: that of pure enacting, without a mind behind it.

It had been equal parts amused and frustrated when the evolution for [Manaflame Guardian] appeared. Unless it was quite far off the mark, that was a shared evolution for [Flame Wisp], and it couldn't help but feel it as a pointed barb, given its continued inability to spawn one 'naturally'.

Tier 3 was still quite weak, even for the first five floors of a goblin dungeon. But it was at least some variance beyond a repeating series of [Lesser Mana Puppets] and [Common Mana Puppets]. And, after all — this had all started because it was tired with artifice. If adventurers wanted a dungeon full of mobs they could grind experience from, Goblin Cave would give them what they wanted.

Due to the symmetries of the mana bellows, there were only three chambers that it trusted it could connect to its old dungeon without the connection messing with the mana flow. It debated which to choose, and then decided on something else entirely: instead of connecting them to its old dungeon, it would dig all the way up to the surface with all three. It had wanted to study the interface between its mana and the surface, and now it was in a position to give itself more room to study. The risk was from any exposure; if it was going to dig a single extra entrance it might as well dig two thousand four hundred and one.

Still. It had been a long time coming. Its mana bellows, filled with various mana constructs and wandering bosses. A dungeon within a piece of abstract mana-manipulation machinery, with a single exit at the very bottom down to its expanded floor 6, and down and down, a whole alternate reality of monumental complexity sitting right next to its original goblin warren. It was the culmination of everything it had considered ever since it had gotten frustrated digging out floor 51, but more than that it was a declaration: that it was something different now. That it was... aware of its situation in the world. That it was working to change it.

Goblin Cave took a deep breath, mana flows all throughout its many layers pausing, and then it pushed up and out, carving through the final feet of rock to the surface. Boulders and dirt cascaded down onto its surface, and its mana touched the wider world, forming whorls of turbulence. Pressure shifted and equalized, forming three new dungeon entrances.