The Sin System: My Wife is Envy

Chapter 75: Dungeon Arc

The dungeon entrance was below the east complex.

Not metaphorically below. A staircase behind a door marked Training Infrastructure: Authorized Access Only that went down three floors below the island’s base level, into a reinforced chamber that the academy had apparently been maintaining since the original construction.

Hiratsuka led us down.

The chamber at the bottom was large enough for all twenty-five of us with room. The gate was already open, a standard D-tier formation, the dark ring stable and consistent, the ambient mana on the other side carrying the cooler, denser quality of a contained environment.

"The dungeon has four floors," Hiratsuka said. "Standard D-tier layout. Central axis, branching corridors, boss room at the terminus of floor four." She looked at the class. "You will split into groups of five for floors one through three. Floor four you reassemble. The assessment is individual performance within group context, which means I am watching how you function together as much as what you produce alone."

She handed the group assignments to Cian, who distributed them without being asked.

I looked at mine.

Anastasia was not on the assignment sheet, which made sense because she was not enrolled. She was standing beside me reading the sheet over my shoulder.

"I will follow you," she said.

"The assignment has five people per group," I said.

"I know," she said. "I will be the sixth."

Hiratsuka, nearby: "Ashford. You are observational status. Do not engage unless the situation requires it."

Anastasia nodded.

We went through the gate.

Floor one opened into a corridor wide enough for six people walking abreast, the ceiling illuminated by the dungeon’s own ambient light, the stone underfoot worn smooth by years of use.

The D-tier population announced itself within thirty seconds.

Stone-type. Low evolution. Three of them around the first corner, holding a twelve-meter stretch of corridor with the commitment of creatures that had decided it was theirs.

The five of us cleared them in the time it took Anastasia to examine the wall texture.

"The stone here is different from above," she said.

"The dungeon generates its own geology," I said.

"I know. I am noting that it is generating a particular type." She looked at the ceiling. "The mineral composition in the upper formations is consistent with the Northern Region’s bedrock. This dungeon was not seeded from a neutral location."

I filed that and kept walking.

Floor one cleared in twenty minutes. Standard distribution, nothing above E-rank, the branching corridors terminating at collection points with higher population density that required brief coordination before clearing.

Anastasia observed the first two encounters and engaged on the third when something got past the group’s left flank. She did not use anything visible from a distance. She moved through it without drama and stood back.

"Observational status," she said, when she returned to my side.

"Yes," I said.

"That was an observation about what happens when the left flank is unanchored."

"Was it."

"Yes," she said, and kept walking.

Floor two had wind-type population.

The ceiling was higher here, which gave the wind-type room to operate. Vertical range made them more dangerous than the stone-type on floor one in ways that required adaptation.

We adapted.

The group’s wind affinity member handled the aerial elements while the rest of us managed ground contact. By the second collection point the coordination had become automatic, the five-person group finding its pattern without discussion. Seven days of ranking bracket competition had forced everyone to understand what everyone else could do.

The floor cleared in thirty-five minutes.

At the floor transition, Anastasia pressed her palm flat against the corridor wall.

She held it there for five seconds.

"The mana density is increasing," she said. "Faster than D-tier gradient."

"I know," I said.

She looked at me.

"You have been tracking it," she said.

"Since the lake readings started changing."

She held the wall for another second.

"The seeding," she said. "This dungeon was not opened naturally. The breach origin the Vice Dean is investigating above, this is it."

"Yes," I said.

"The Stars."

"Yes."

She removed her hand from the wall.

"Then the boss room is not a D-tier boss," she said.

"No," I said.

She looked at the transition door to floor three.

"What is the plan," she said.

"Find Tessira," I said. "Then floor four."

She nodded and went through the door.

***

Floor three was different before we reached the first corner.

The ambient light had shifted. Still the dungeon’s own illumination, but the quality had changed, the source running under different parameters. Warmer at the edges. The shadows defined more sharply.

The population here was not wind-type or stone-type.

The first group we encountered had coordination. Four of them moving together with the deliberate spacing of units that had been briefed rather than instinct-driven. They held a choke point at the first branch junction and waited for us to come to them rather than charging.

"That is not D-tier behavior," Calder said.

"No," I said.

"How is it not D-tier behavior."

"The dungeon is upranking," I said. "Something is feeding additional mana into the formation. The population is evolving faster than the standard gradient."

We cleared the junction group and moved.

The upranking was visible in every subsequent encounter. Not different from floor two. The individual capability of each creature was advancing in increments, B-tier edges rather than full B-tier classification. But the coordination was what mattered. F

loor three’s population had stopped being territorial and started being tactical, a category shift that changed how you approached each engagement.

We adapted again, more slowly this time.

At the second collection point, one of the five took a hit hard enough to require Sanguine Pulse recovery time before moving. I held position while the group managed the remaining population, running Crimson Veil against three simultaneous contacts and finding the margin thinner than I had wanted.

Anastasia handled one of the three.

"Observational," I said.

"That was also an observation," she said.

We found Tessira at the third branch of floor three’s central axis.

She was not in trouble exactly. The situation was at the edge of her capacity in the way of something that had gone from manageable to difficult without a clean resolution point in between.

Eight creatures. Mid-tier individual capability. They had the same coordination the rest of floor three had been showing, which meant they were not making the predictable territorial choices Tessira’s technique set was built to counter.

Sylph was fully extended. The wind was doing most of the work, a sustained perimeter technique keeping the eight from closing distance simultaneously. But a perimeter at that scale had a mana cost, and managing eight coordinated mid-tier threats had a time limit.

She had maybe four minutes before the margin compressed.

We came around the corner and she did not look up because she had already tracked us by the sound of our approach.

"Junction on the right needs to be closed first," she said. "Two of them keep retreating to it and coming back. If the junction is closed they lose the coordination anchor."

Anastasia moved to the junction before I had finished processing the instruction.

She closed it.

The two creatures that had been retreating to it did not retreat to it anymore. They rejoined the main group, which reorganized around the change, and the reorganization took four seconds during which the perimeter had less pressure.

Tessira used the four seconds.

Sylph’s technique shifted from perimeter maintenance to targeted, and three of the eight stopped being a problem inside the window. The remaining five met the rest of us coming from the corridor and the outcome was no longer complicated.

Tessira released the perimeter technique and breathed.

"Thank you," she said, in the direction of Anastasia.

"You identified the anchor correctly," Anastasia said. "I just closed it."

"How long were you watching," Tessira said.

"Long enough," Anastasia said.

Tessira looked at her hands. The mana expenditure was visible in the slight pallor that came with sustained high-output work.

"Drink this," I said, and held out the healing compound from the alchemy session.

She took it and looked at it.

"You kept it," she said.

"Standard practice," I said. "One compound per dungeon entry."

"Seren would be pleased," she said, and drank it.

The warmth hit in approximately thirty seconds. The pallor pulled back. She rolled her shoulders and picked up her bag.

"The boss room," she said.

"Floor four," I said.

"What is up there."

I told her about the mana density, the upranking, the Stars, the ritual anchor in the boss room. I told her quickly because we were still on floor three with a transition to make and the mana density had been increasing the entire time we had been talking.

Tessira listened without interrupting.

"And Hiratsuka knows," she said, when I finished.

"She knew before we entered."

"She sent us in anyway."

"The gate sealed forty seconds after the boss room opened," I said. "On a timer. The only exit is through the boss room."

Tessira looked at the ceiling. Then at me.

"Right," she said.

Sylph settled around her shoulders like a mantle.

We went to floor four.