The corridor opened and kept opening.

  Not into a chamber. The corridor itself expanded, the walls pulling back gradually over a hundred meters until the passage was no longer a passage in any meaningful sense but a thoroughfare, the width of it broader than the Cours Centrale pza above ground, the ceiling climbing with the walls until the mineral crystal formations up there were distant, elevated, the light they produced falling from a height that made the floor feel like the bottom of something rather than the surface of something.

  Dark blue.

  The walls had changed material at some point in the descent, the iron-red stone of the upper floors repced by something denser and darker, a deep blue-bck rock that caught the crystal light from above and returned it in fragments, the wall surface not reflective but present, the color of deep water seen from above.

  The formations in the ceiling were rge.

  Large enough that their light output was genuine, each crystal the size of a person, some rger, the clusters of them producing overpping pools that merged into something approaching actual illumination across most of the floor's visible surface. Not daylight. Not the upper floors' amber or white. Something cooler and more complete, the blue of the walls tinting the crystal light as it fell.

  Aris looked at it.

  He looked at the walls disappearing into the distance on both sides. He looked at the ceiling formations. He looked at the corridor extending ahead of them until the light gave out at a distance he couldn't estimate.

  "This is going to take ages," he said.

  "Yes," Colette said.

  "The upper floors we could cover systematically," he said. "Each section, each wall, the transitions. This," he looked at the width of the space, "we'd need a week at this level."

  "We don't have a week," she said.

  "We don't have a day," he said. "Our mana—"

  "I know," she said.

  She stood in the corridor's new scale and looked at the space and was quiet for a moment in the specific way of someone arriving at a decision they had been hoping to avoid needing to make.

  Then she closed her hand at her side and opened it and looked at the palm.

  "Step back," she said. "Give me room."

  Sovereign rose.

  The crowned form ascending above Colette's skin with the familiar deep blue glow, the amplification quality of it present even without a target to amplify, the Eido's fundamental nature expressing itself in the air around her.

  Then it did something Aris had not seen it do.

  It dissolved.

  Not dismissed, not recalled, the way an Eido went when its user stopped maintaining it. Dissolved, the form losing its coherence deliberately, the crowned silhouette coming apart at the edges and continuing to come apart, the structure dispersing outward while the light remained, the Eido becoming the energy it was made from rather than the shape it usually held.

  Green mana.

  It spread from Colette in a cloud, dense near her and thinning as it extended outward, the green of it different from Marionette's green, cooler, less warm, the color of deep still water rather than growing things. The cloud reached the corridor walls and found the passages branching from the main thoroughfare and went into them, the mana thinning further as it divided, each branch taking a portion of the whole.

  Colette's eyes were closed.

  Her face had the specific stillness of someone whose attention had gone somewhere other than their body, the outward expression of deep internal focus, and the green of the dispersed Sovereign moved through the floor's spaces around them with the slow exploratory quality of something being guided rather than something running free.

  "Colette," Aris said quietly.

  No response.

  He looked at her face. Still, eyes closed, breathing slow and deliberate.

  He looked at the green moving through the dungeon around them, finding passages and chamber spaces and the transitions between them, the mana pressing into the floor's geography like water finding every crack.

  "Right," he said, to himself.

  He stood beside her and watched the corridor and the branching passages and the green moving through all of it, and he watched the approaches from every direction because she had asked him to look after her and he intended to do that with the specific thoroughness he brought to things he intended to do.

  The green moved for two minutes.

  Then it stopped.

  Then it came back.

  From every passage simultaneously, the dispersed portions returning along the paths they'd taken, reconverging in the corridor's space around Colette, the mana thickening again near her as the portions rejoined, the green reassembling from the outside in, the cloud rebuilding its density and then building further, and from the rebuilt density Sovereign emerged, the form reconstituting from the energy as naturally as it had dissolved into it.

  The crowned silhouette settled above Colette's skin.

  She opened her eyes.

  She looked at Aris and then at the floor around them.

  "Nothing," she said.

  "How far did it reach," he said.

  "Two hundred meters in every direction approximately," she said. "The main corridor ahead, six branches left, four right, three chamber spaces." She looked at the ceiling. "Nothing of what we're looking for."

  She brought Sovereign back in, the Eido settling fully.

  "Why didn't you do that on the floors above," Aris said.

  "Mana consumption," she said. "Dispersion is expensive. The upper floors were small enough to cover physically without spending what dispersion costs." She looked at the thoroughfare's scale. "Down here the physical approach would exhaust us before we'd covered a fraction of it."

  "So now you've spent the mana anyway," he said.

  "On information rather than combat," she said. "Better accounting." She looked at him. "Your turn."

  "My turn," he said.

  "Your reserve is higher than mine," she said. "Your abilities are precise and contained, they don't consume the way Sovereign's amplification does. You have more left."

  He looked at Void above him.

  The Eido had recovered during the Hollow Knight's rest period, the form denser than it had been in the corridor, the mask face clear.

  "I've never dispersed it," he said.

  "You've never needed to," she said. "The mechanic is the same for any Eido. You dissolve the form into its base mana and you direct the mana as a field rather than a shape." She paused. "The difficulty is conceptual. An Eido is an external representation of yourself, of what you fundamentally are. To disperse it you have to extend that selfhood outward. Picture yourself rger. Give Void a bigger field to express itself across."

  "Picture myself rger," he said.

  "Not physically," she said. "The sense of self that Void comes from. The thing that made it what it is. Extend that outward rather than holding it close."

  He looked at Void.

  The dark featureless form. The smooth mask. The stillness of it, the specific quality of an Eido that had always been about presence and contact and the precise application of force at the point where something needed addressing.

  He thought about the clinic.

  About six years of people coming through the door with dungeon ailments and Void pressing close to each one, finding the specific thing that needed addressing and addressing it with the full attention of an Eido that had been built for exactly this.

  He thought about what Void was, at its foundation.

  The thing he had named in an orphanage when Edric asked him what he felt like.

  Void, he had said. Like a space where something should be but isn't.

  He had been ten years old and he had meant it as a description of himself and Edric had looked at him and said that spaces where something should be were exactly where things grew.

  He held that.

  He held the foundation of what Void was and he let it expand.

  Void dissolved.

  Slowly at first, the edges of the form losing definition, the dark of the silhouette coming apart into the mana it was made of, the mask face the st thing to go, present and then not present, and the mana that remained was dark purple-bck, the color of Void's form transted into its constituent energy.

  It spread.

  Not the warm exploratory spread of Sovereign's green. Something that moved differently, that found the floor's spaces with the specific attention of an Eido built for finding things, the dark mana pressing into passages and chambers with the focused quality of something that knew what it was looking for and was looking for it completely.

  The trail of it in the main corridor was visible, a river of dark moving forward through the crystal light, the purple-bck standing against the blue of the walls with crity. Where it divided into branches it divided cleanly, each portion carrying the full attention of the whole, the mana finding the floor's geography and covering it.

  Aris kept his eyes open.

  He could feel it. Not the way he felt Void when it was close, the immediate sensation of the Eido above his skin. Something rger, the awareness of a field rather than a form, the floor's spaces existing in his peripheral awareness as presences rather than abstractions.

  The mana moved outward.

  Further than Sovereign's green had reached, the range extending, the dungeon opening itself to the field in the specific way that the dungeon opened to things that were part of its own energy register.

  Further still.

  And then the field found something.