The difference was visible before the combat began, in how the mutants occupied the space. Not the chaotic concentration of the first chambers but a distribution with something resembling the positioning logic of creatures that had survived long enough in a selection system to have learned, however primitively, how to be in a room with others trying to be in the same room.

The weakest ones at the edges... The strongest toward the center.

The cannibalizing had weakened them here too, but the weakening was less pronounced than in the earlier levels.

Liora’s spirit fire covered the left sector of the third chamber, and in the margin of attention Ren could give it while managing the right sector with the Mantis, he observed something he filed away. The Mantis at Gold 1 produced a synergy with the spirit fire that hadn’t been available at Silver 3; the cutting power of the wind at the new rank was compatible with the propagation of the spiritual flame in a way that made the two techniques amplify each other in the area where they overlapped, each one creating conditions that made the other more effective.

He noted it for later.

They cleared the third chamber and moved to the stairs.

The fourth chamber broke the pattern.

Not in having or lacking mutants, but in their level. Ren had expected Gold 1, following the consistent step-up between each chamber, but what he found was something sitting just below that threshold: the liminal state where a beast’s system had enough energy for the rank but hadn’t completed the stabilization cycle. Close enough to register as almost Gold, far enough to register as not quite there.

"Are they simply incapable of crossing that limit?" Hikari asked from her lateral position.

"They can cross it because I’ve already seen them do it," Ren said. "And they’ve improved. Before, there were fewer mutants per chamber and the progression between levels was roughly half as fast."

Something had accelerated... Whatever was managing this process had gotten better at it.

In the fifth chamber they found something newer and more difficult to read, even for Ren. Many of the cave’s runes were overwritten in a bright purple liquid, the original patterns partially obscured beneath the new ones in a layering that hadn’t been done hastily. The work had affected the internal structure of the stone.

And these mutants were indeed Gold.

Real Gold 1, with the genuine aura that distinguished an actual evolved creature from a mutant that had grown larger and stronger while remaining functionally below the threshold.

The cannibalizing hadn’t stopped, and the size increase was consistent with what the chambers below had shown, but the overwritten runes had accelerated something in the process that the raw selection alone hadn’t been producing.

There was a clear difference between big mutants with Gold-level physical size and strength and mutants with a true Gold aura and the system to match it.

Selthia appeared to have refined her approach.

The lower chambers had served as fuel. The mutants there fed into the ones above, which used that energy to reach ranks they wouldn’t have reached through natural development. A brutal and efficient selection in the coldest sense of both words. The pyramid of it was visible in the layered marks across every body in every chamber they had passed through.

The fifth chamber was the first that required genuine attention.

Not the sustained, pressing kind, but the kind where letting the mind wander had a cost. Liora adjusted the intensity of the spirit fire. Ren adjusted the range of the wind blades. The group covered the flanks with more deliberate structure than in the earlier chambers, the formation tighter, each person closer to their assigned anchor point.

The fifth chamber cleared, but it took longer.

♢♢♢♢

The sixth chamber was Gold 2, and it was different in ways that started with the entrance.

The opening was wider than any of the previous ones, wide enough that the group could enter in formation, which was relevant because the chamber itself was also wider. More space for the mutants inside to use, which meant more directions from which an engagement could arrive.

Gold 2 mutants moved differently from Gold 1. Not only faster, but with less of the residual hesitation that the lower ranks carried.

When the group entered and combat started, the mutants responded with something approaching deliberate positioning: the larger ones moving to intercept while the smaller ones consolidated in the rear, not out of instinct but out of something that had learned to do this.

The cannibalizing marks were present but less extensive on the strongest of them. The ones that had absorbed the most from below had more structural damage; the ones that had consumed less were more intact but also lower in the overall hierarchy of the chamber. Whatever the selection was producing, it wasn’t clean. The strongest had gotten there by a process that had cost them.

The wind and the spirit fire still worked, still amplifying each other enough in their overlap zone, but the sustained output required to clear this chamber was noticeably greater than the fifth. Ren felt it in the rate of mana consumption rather than in effort; the Mantis at Gold 1 had range and precision but the targets here were absorbing more before they went down.

Lin took direct responsibility for two of the larger mutants.

The sixth chamber cleared. The group was quieter after it.

The seventh was Gold 3.

The entrance to the seventh chamber radiated the kind of acrid smell that spoke not of death but of corrupted mana concentrated in a space that had been occupied by high-rank entities for a sustained period.

The walls here had more of the overwritten runes more densely than anywhere above; layer on layer in some sections, the original ruin patterns nearly invisible beneath the accumulated work.

Gold 3 mutants were what the selection had produced at this level were creatures that had consumed everything below them in the system and carried it.

The marks of that consumption were everywhere on their bodies, old scars over new ones over older ones still, layers of forced development visible as physical text. They were not healthy creatures at Gold 3. They were creatures that had been driven to Gold 3 through a process that left damage at every level, and the damage hadn’t fully healed between advancements because the process hadn’t given it time to.