Death, absolute death.

The death of a slime by the horde of ants gave rise to another minion in the dungeon. This new slime was different, he was hard-boiled and one hell of a good detective. It was his mission to seek vengeance. The hunt started slow, but after he ate a few corpses and learned their biology, the ants were a lot easier to kill en masse.

It wasn't perfect, he took a lot of damage, almost died in a cave-in, and countless other things a rough and tumble detective has to face on the job. In the hardship, he evolved. He became a slime acclimated to the depths of despair he found himself in. This evolution gave him an edge that he used to cut down the gang of insects.

After his accomplishments, he returned to the core that hired him, his Client. He demanded his payment be the revival of his sister. The Core, lacking any intelligence, didn't understand. Getting mad enough caused the core to revive the first slime, the slime of starlight, the slime named Shimmer.

So naturally, since Shimmer has exactly one emotion, and that emotion is friendship, she went to the ant colony the dungeon had recently assimilated. Her first and only instincts were to make friends. Friends with red ants, with the reasoning of 'they like plants, we have that in common.'

So they became friends. Enough said.

These friends got into a lot of trouble. The ants mutated, the slimes changed as fate brought them closer together, and birds appeared in the dungeon. These birds were killed by an explorer and accidentally fed to the dungeon, since this human invader was a timid child who knew how to incompetently use a sling. However competence doesn't factor when someone uses exploding bullets, so he managed his first delve into the dungeon. It didn't go well when he set the entire place on fire and stuck his hand into acid.

His fault for blinding sticking his hand into a hole in the earth. Yes, this is victim blaming. No, I don't care. His fault for not playing nice.

After he left, an adventuring party of four made their appearance. They were less interested in fighting, and more in the discovery of what grew in a place so isolated. This adventuring party was different as their classes were so specific. A mage that was fueled by emotion, called the Incanter of Intent. A bard that doesn't use music, the Muse of Synesthesia. A rogue whose senses were unmatched as a Mastermind of Perception. And a melee fighter who has yet to fight anyone.

A case of content theft: this narrative is not rightfully on Amazon; if you spot it, report the violation.

So they find themselves in the burned dungeon, have no idea what's going on, and the bard just adopts Shimmer. Her reasoning was that the slime 'feels like its purring' so naturally the instinct innate to all living creatures of 'pet nice kitty' took over. Lack of survival instincts on full display. Get used to it, that's a reoccurring theme.

These adventurers left, but they littered. They didn't think it mattered, to just leave trash behind, but it did matter. The dungeon used it to learn what culture is, about tools, food, writing, and even magic items. So with an intelligence of ten, the dungeon Core reached the unmatched levels of "close enough to sapient to maybe be that." No that's not a direct quote, this is an unreliable narrator.

So they left to go hunt down whoever set fire to the dungeon. They thought it was a competent mage who was siphoning power from reality itself. They were wrong, but oh well, they might figure it out eventually.

In the wake of destruction and two adventuring parties, the dungeon had a lot of mana to play with. So it evolved the ants so much that they stopped being dungeon monsters. Each member of the colony with stone skin, mana stones for hearts, a slight flame affinity, and the name Ancient Ants as they started a cult. The colony diverged with all the mutations to fill out niches such as aphids, springtails, and spiders. Spell infection spiders... who became great friends with that Noir slime from earlier who recently took the name 'Warden of the Vault' or "W.Vault" for short, or "WV" for even shorter.

Well, Vault's little spider friends dressed in silken rags to help with the various evolutions he had gone through. Forces of yin and yang made it so each evolution was paired with Shimmer, when one grows brighter, the other grows darker. This worked really well for the fact that Shimmer had learned how to eat fire and now glowed. Vault, dressed in his mana silk robes, accidentally invented the string telephone and used it to talk to the Dungeon.

Or at least.... hear the Dungeon's lack of thoughts as it ate birds. Birds it added to its dungeon and twisted horribly until they could not be considered alive. The dungeon liked this, because they were quote "full of mana"

No, they were full of cancer you dense motherfu-

So these birds, mutated to the point they could survive the dead mana became vessels. They would carry seeds of Sage grass, a species also evolved to survive dead mana. Combined, they komokazied the dead mana that surrounded the dungeon. By its very definition it was a wall of "reality said no" but turns out if you beat your head against a brick wall long enough, eventually you stop losing.

They still weren't winning, not for a long while, but hey, close enough.

Thats also a recurring theme in the story.