Yuan didn't announce himself.
He came through the chamber entrance at the wall's edge, read the positions in under two seconds, Fire Imp airborne at eleven o'clock, wind constructs flanking left, the two unclassified quadrupeds pushing center, and activated Shadow Step toward the most immediate threat.
The Fire Imp was lining up a shot at the clustered students.
He came out of the skill directly above it, grabbed the back of its neck with both hands, and used the downward momentum to drive it into the floor before it could fire. The impact extracted the core automatically, a reflex he hadn't consciously initiated, and the Imp dissipated before Zhang Wei's group had fully registered that something had changed.
One of the wind constructs turned toward the new variable.
Yuan was already moving.
He took it apart the way he'd taken apart the Earth Elemental, circuit interruption, precise contact, the construct settling rather than dying. The second wind construct charged and he sidestepped it with the Agility-adjusted timing that still surprised him slightly, like a calibration he kept forgetting he had, and put his palm into its channel cluster on the way past.
Two down, three seconds elapsed.
The chamber had gone quiet in the way that large groups go quiet when they've stopped being able to process what they're seeing fast enough to react to it.
Zhang Wei said, "Shenzi?"
---
The quadrupeds were the problem.
They were something he didn't have a field guide entry for, low to the ground, dense mana composition that his Sense was reading as cold and compressed in a way that suggested impact-absorption as a native trait rather than an acquired one. They moved with the loose-limbed readiness of things that had learned to wait for targets to commit before responding.
He didn't commit.
He circled left, watching their tracking adjust, and threw a piece of loose stone at the right one's flank. It flinched, not much, barely a shift in weight, but enough to open the left one's attention for a half-second. He took the half-second, Shadow Step carrying him inside the left creature's guard, and hit the mana cluster at the base of its skull with everything the Strength-thirteen could produce.
The cluster ruptured.
The creature went down and didn't get up.
[Ding!]
[C-Rank Umbra Hound defeated. Experience +90]
Umbra Hound. He filed the name.
The second one charged the moment its packmate fell, faster than it had moved before, the restraint gone, and Yuan had to burn Shadow Step to get clear of the initial rush. He came out behind it and hit the same target point, same force, same result.
[Ding!]
[C-Rank Umbra Hound defeated. Experience +90]
He stood in the center of the chamber with five monsters' worth of dissipated mana settling around him and turned to face Zhang Wei's group.
Five students. Four faces he didn't know and one he'd known since their first year orientation, when they'd both been placed in the lowest-ranked dormitory wing and had bonded over the shared experience of being objectively the least impressive people in any room they entered.
Zhang Wei looked at him for a long moment.
Then he said: "What."
---
It wasn't a question. It was a complete sentence expressing a complete emotional state.
Yuan crossed the chamber and checked the group for injuries, two with significant cuts, one with a shoulder that wasn't sitting right, all of them functional in the sense that mattered. He moved through the assessment efficiently and let Zhang Wei's processing time run out while he worked.
"Your arm," he said to the student with the shoulder issue. "Don't use it."
"I wasn't planning to," the student said faintly.
"Shenzi." Zhang Wei had followed him around the chamber and was now standing two steps behind him with the expression of someone who had decided not to ask the obvious question and then immediately decided to ask it anyway. "You're F-rank. You have Mana Sense."
"I did have Mana Sense, yes."
"And now you're," Zhang Wei gestured at the dissipated monster residue filling the chamber. "doing that."
Yuan had been running this conversation in the back of his mind since the Gargoyle King fight. He'd constructed several versions of it and found that they all had the same problem: Zhang Wei was not stupid, and partial truths had to be structurally sound to hold under scrutiny, and Zhang Wei was the kind of person who applied scrutiny to everything involving his friends as a function of caring about them.
"The anomaly," Yuan said. "When it hit, something happened. I think the mana surge triggered something latent."
"A latent ability."
"Some kind of combat orientation. Movement-based. I'm still figuring out the parameters."
Zhang Wei looked at him with the specific expression of someone deciding how much they believed what they were being told. Yuan held eye contact and kept his face neutral and thought about the SSS-rank notation on his status window and the word hidden.
"You've been training," Zhang Wei said. It wasn't quite an accusation. More of an offering, a version of events that was more comfortable than the alternatives.
"I've been training," Yuan agreed, which was technically true in the sense that he'd spent the last two hours in a C-rank dungeon developing practical competency through direct application.
Zhang Wei held the look for another two seconds. Then something in his face resolved into the particular trust of someone who had decided that their friend was keeping something back and that this was probably not the time to push on it.
"Okay," he said. "Okay. We deal with it later."
"Later," Yuan agreed.
---
They moved to the chamber wall and Zhang Wei gave him the situation in the flat, organized way he always processed crises, sequentially, without editorial, the facts before the feelings.
Approximately eighty students total in the dungeon at exam start. The main hall shelter had sixty-something, which Yuan already knew. The remaining twenty had fragmented into smaller groups across the dungeon's upper levels, some sheltering in defensible positions, some actively moving toward the main hall. Zhang Wei's group had been five of those twenty, pushed deeper by a monster surge rather than toward safety.
Two academy staff confirmed active, Instructor Shen Bo in the main hall, someone else Zhang Wei's group had lost radio contact with forty minutes ago. Emergency extraction beacons transmitting but no topside response confirmed.
"They know we're here," Zhang Wei said. "They just can't get to us. The anomaly sealed the gates completely, nothing comes in or out until it resolves."
"Until someone resolves it," Yuan said.
"What?"
"Nothing. What's the monster density like between here and the main hall?"
Zhang Wei's group exchanged looks. The one with the shoulder, Yuan had caught his name, Peng, E-rank barrier type, pulled out a crumpled hand-drawn map and spread it against the wall. Rough, inaccurate in the ways that maps drawn from memory under duress were always inaccurate, but the broad strokes were useful.
"Heavy in the central corridor. We tried twice. There's something coordinating them, not intelligently, more like territory behavior, but the density is too high for our group to push through."
Yuan looked at the map. Looked at the path to the lower levels. Looked at the timer in the back of his mind that he'd been running since the quest notification.
Nineteen minutes.
"There's a way through," he said. "Deeper, not around. The lower levels opened during the boss fight, new paths. I came up through them."
"Deeper," Peng repeated, in a tone that indicated his opinion of this plan.
"The anomaly has a source. If we reach it and neutralize it, the exits unseal." Yuan kept his voice flat, factual, the way you present information that is alarming but true. "If we don't, the dungeon upgrades again in," he checked the count "nineteen minutes."
The chamber went quiet.
Zhang Wei said: "Upgrades to what rank?"
"I don't know."
"You don't know."
"No."
Another silence. Zhang Wei looked at the map, then at Yuan, then at the four other students in their group. Then he straightened up and put the map in his pocket and said "Right" in the tone of someone who had completed the available calculations and arrived at an answer he didn't like.
They were moving when Yuan's Tremor Sense registered the new signature from the lower corridor entrance.
The density was wrong for C-rank, too consolidated and deliberate, with the specific quality of mana that his sense was learning to associate with things that had stopped reacting to their environment and started imposing on it.
It filled the corridor entrance. It had four limbs and a body plan that suggested something between reptile and architecture, and when it exhaled the mana distortion around it bent the air visibly.
His system notification appeared before he'd finished reading it physically.
[Ding!]
[Monster Detected: Dungeon Serpent]
[Rank: B−]
Behind him, Zhang Wei said: "Shenzi."
"I see it."
"That's not C-rank."
"No," Yuan said. "It isn't."