They didn't sleep, not really — just sat pressed into a narrow side alcove for a few hours while the roar of the awakened vault gradually settled into something more like a low, restless murmur, and traded the same handful of useless plans back and forth until exhaustion made the choice for them anyway.
"He's alive," Stephan said, for what felt like the tenth time, more to himself than to Xavier. "They dragged him off. Dragging implies a destination. Destinations imply he's still needed for something."
"That's a very generous read of 'grabbed by an army of skeletons.'"
"It's the read I'm choosing. Feel free to pick a worse one if it makes you feel better."
Xavier didn't have a worse one, mostly because he'd spent the last several hours refusing to let himself think that far. He spread the map across his knees for the dozenth time, tracing the same corridor with a finger gone numb from cold stone, as if staring at it hard enough might reveal a passage he'd somehow missed the first eleven times. It didn't. The map ended, as it always had, at the edge of the vault chamber itself. Whatever lay beyond that point had never been charted, or had been charted once and then deliberately left off, which was its own kind of unsettling thought.
"Anything?" Stephan asked, not for the first time.
"Same nothing as an hour ago. Whatever's past that chamber, nobody who mapped this place ever saw it, or came back to say so."
"Comforting."
"I said it'd be dark and full of skeletons before we left the hot spring. I stand by dark and full of skeletons."
Stephan let out a short, humorless laugh and said nothing else for a while, which was somehow worse than his usual running commentary. Xavier let the silence sit. There wasn't much comfort he could offer that wouldn't have sounded hollow coming out of his own mouth.
He thought, too, though he didn't say it out loud, about Elrick's parting words in the study — that whatever six hundred years of loneliness had done to Veythar, it probably wasn't nothing. It felt like a strange thing to hold onto while their friend was missing somewhere in the dark, and yet he found himself holding onto it anyway, a small, stubborn thread of doubt about whether "monster" was really the whole story here.
"You're doing the thinking face," Stephan said, watching him in the dim light. "The one where you're not actually talking to me anymore."
"Just turning things over. Nothing useful yet."
"Turn them over faster. I'd like my friend back before I turn into a skeleton myself out of sheer boredom."
"Something's directing all of this," he said slowly. "The skeletons, the timing, all of it. Something smart enough to want Bruce alive for a reason."
"Veythar?" Stephan questioned.
"Veythar."
Stephan was quiet for a long moment after that, turning Ember slowly in his own lap, firelight from the alcove's single dying torch catching along the blade in a way that made him look, for once, considerably older than his usual reckless grin ever let on. "Do you actually believe that? What Elrick said? That there might be more to him than just... this?"
"I don't know," Xavier admitted. "I want to, I guess. But that's not the same thing as believing it. Right now, I mostly just want Bruce back, and I'll take whatever version of Veythar gets us there fastest, sympathetic or not."
"Fair. Extremely fair." Stephan leaned his head back against the cold stone, eyes closing, though Xavier doubted he was actually anywhere close to sleep. "For the record, though, if he does turn out to be some tragic, misunderstood thing, I reserve the right to be annoyed about it. After everything today. I've earned that much annoyance."
"I'll let you have it when... if... the time comes," Xavier said, and let himself, finally, close his own eyes for a while, not sleeping so much as resting them, the weight of the day settling into his bones in a way that had nothing to do with exhaustion and everything to do with the particular, specific dread of not knowing whether a friend was still breathing somewhere in the dark below them.
"Can I ask you something?" Stephan said eventually, eyes still closed.
"Go ahead."
"If it comes down to it... if there's no talking, no reasoning, just him or us... are you going to hesitate? Because of the sympathetic thing?"
Xavier considered the question longer than he expected to need. "No," he said finally. "Bruce comes first. Always. If it's him or Bruce, there's no version of that where I hesitate." He paused. "But I'd rather it not come to that, if there's another way. I think Elrick would want that too, honestly. He didn't say listen to him instead of fighting. He said listen if there's a chance to. Those aren't the same instruction."
"You've clearly thought about this more than you let on."
"I've had a while in a dead silent crypt with basically nothing other than my thoughts. Sue me."
Stephan huffed out something that was almost a laugh, and for a while after that neither of them said anything at all, the low murmur of the vault beyond their alcove the only sound in the world. Somewhere in that silence, without either of them quite noticing the transition, they both actually did sleep for a while — not long or restful, really, but enough to blunt the sharpest edges of the exhaustion clawing at both of them, and when Xavier's eyes finally opened again, the alcove's dying torch had guttered down to almost nothing, and the murmur beyond it had, if anything, grown a little louder.
"Time to move?" Stephan asked, already awake, already reaching for Ember.
"Time to move," Xavier confirmed, and pushed himself upright, every muscle protesting the decision, the map folded carefully back into his coat.
They pressed onward at first light, or what passed for light this deep underground — a grim, determined march back toward the great vault chamber, weapons ready, nerves worn thin from a night of half-sleep and worse imaginings. The corridor felt narrower going back, or maybe that was just the two of them walking it with fewer illusions about what waited at the end of it.
"You hear that?" Stephan asked once, going still.
Xavier listened. Nothing but the low, restless murmur they'd been hearing for hours now, closer than it should have been. "That's the vault. Still awake, it would seem."
"Fantastic. Awake and waiting is so much better than awake and looking for us."
"I didn't say it was better. I said that's what it is."
They passed the rune-locked door on the way, discs still sitting patiently in their earth-fire-wind-water alignment. Xavier paused there just long enough to run a hand across the cool stone, some small, irrational part of him half expecting it to have changed overnight. It hadn't. They passed, too, the alcove where the shield had nearly betrayed them the night before, still leaning exactly where Stephan had carefully set it back, and he gave it a wide, deliberate berth this time, muttering something under his breath that sounded suspiciously like an apology directed at a piece of rusted metal.
Xavier didn't comment. There wasn't much room left in him for anything but the growing, low-grade dread building with every step closer to the main chamber, the murmur ahead thickening from a distant hum into something with actual texture to it — grinding, shifting, a sound like a great deal of loose stone settling all at once.
"That doesn't sound like a room full of standing skeletons anymore," Stephan said, slowing.
"No," Xavier agreed. "It really doesn't."
They approached the chamber's threshold together, weapons raised, moving with none of the careful stealth from the night before. There seemed little point in it now, not with a sound like that filling the air ahead of them, not with Bruce somewhere past it and every second spent creeping costing them time they couldn't afford to lose.
The chamber, when they reached it, was no longer the still, orderly rows of standing dead they'd first walked past. It was a mess of bone, piled and shifting, hundreds of skeletons no longer standing individually at all but pressed together in the chamber's center in a heap that was, disturbingly, beginning to move with a single, unified purpose.
"...What is that?" Stephan said, taking an instinctive step back.
Xavier had no good answer. The pile shuddered, bones grinding and locking together with a wet, awful sound that had no business coming from anything already dead, limbs interlacing into something with rough, oversized proportions — a torso built from ribcages stacked and fused, arms thick with layered femurs, a head assembled from a dozen skulls pressed into one crude, many-jawed mass. It rose, slowly, impossibly, to a height that put the chamber's own ceiling at risk, ancient armor scraps embedded haphazardly across its shifting bulk like scavenged trophies.
"They're combining," Xavier said, backing up alongside Stephan, mind racing to catch up with what his eyes were reporting. "The whole horde. Into one thing."
"That feels like it should not be allowed to happen," Stephan said, drawing Ember, voice climbing toward something between terror and, infuriatingly, excitement. "That feels like a war crime against basic anatomy."
"Do you see Bruce anywhere in... no, don't answer that. I don't actually want to know if the answer is yes."
"He's not in it," Stephan said anyway, scanning the shifting mass with grim thoroughness despite Xavier's protest. "I'm fairly sure. It's all skeleton parts. He'd stand out."
"Small mercies," Xavier muttered, though the relief lasted only as long as it took to remember that not seeing Bruce in the colossus didn't actually tell them where he was. If anything, it made things worse. If he wasn't part of whatever this was, that meant something else, somewhere else, was still holding onto him, deliberately kept apart from the rest of this display of raw, mindless assembly.
"He's somewhere past this thing," Xavier said, mostly to steady himself. "Has to be. This is a wall."
"Then let's go through the wall," Stephan said, with the particular grim cheer he reserved for situations that had stopped being survivable through caution and started requiring pure, committed recklessness instead.
The colossus turned its assembled, many-eyed skull toward them with a slow, grinding creak, and let out a sound that was less a roar than a chorus — hundreds of small, dry voices layered into one vast, hollow howl.
"Plan?" Stephan asked, already settling into a ready stance.
"Working on it," Xavier said, flame gathering along his blade, though even as he said it, he had the distinct, sinking feeling that whatever plan they came up with was about to be tested very, very hard.
There was no time to refine it further. The colossus's first stride shook loose dust from the ceiling in a fine, drifting rain, and then it was moving, far faster than something built from a hundred mismatched skeletons had any right to move, and whatever careful strategy either of them might have assembled given another minute simply evaporated under the immediate, screaming need to not be standing where it was about to land.
Xavier threw himself one way, Stephan the other. The ground where they'd both been standing a heartbeat earlier caved in under a fist the size of a cart, and somewhere in the scramble that followed, any remaining trace of a plan gave way entirely to instinct, adrenaline, and the simple, stubborn refusal to be the reason Bruce never made it home.