The water came from a crack in the wall where the rock was damp and cold. Not a stream, just a slow weep of moisture that dripped into a natural basin worn into the floor.

Eren crouched next to it and drank with cupped hands. The water was metallic and gritty but his body needed it so badly that it tasted like the best thing he’d ever put in his mouth.

His feet were raw. The skin between his toes was red and cracked and there were blisters on both heels that his Pain Resistance was turning from sharp stings into dull warmth. The soles of his feet were tougher than they’d been a month ago, thick calluses built from twenty-eight days of barefoot forest living but ninety minutes of full sprint over rocks and roots had pushed even that protection past its limits.

He drank more water and pressed his back against the tunnel wall. The stone was cold through the dried filth on his skin and it felt amazing.

His Primal Senses were scanning constantly, a low hum of awareness that painted the tunnel system in overlapping layers of sound and vibration and thermal data. The gorillas were still moving somewhere below him, maybe four or five minutes away. He could hear the faint scraping of their massive hands against stone walls as they navigated passages too narrow for their bodies.

They were quiet about it though. No screaming, no roaring, no smashing through walls even though they probably could’ve. Just the careful controlled movement of something that knew exactly what it was doing.

Eren kept drinking while his Primal Senses were screaming at him to move but his body needed this water more than it needed to run. And he knew from two failed rest attempts earlier that the gorillas would find him regardless.

Better to drink now while he had the chance.

The sound changed when they got close. Not louder but different. The scraping stopped and the vibrations in the stone floor shifted from rhythmic footsteps to something irregular and deliberate.

They were stalking him. The female was coming from below and the male was circling through a wider passage to cut off his forward route.

Eren kept drinking without moving his eyes from the tunnel ahead.

Come on. A little closer. Show me which direction you’re going to close from.

The attack came from behind and above at the same time.

A sharp stone from the female, aimed at the back of his skull from a narrow passage he’d dismissed as too small for either gorilla. His Predatory Reflex caught the motion a fraction of a second before impact and his body moved sideways and down, flattening against the basin while the stone cracked into the wall where his head had been.

The male charged from the wider tunnel ahead, three and a half meters of grey muscle filling the passage like a living wall.

Eren jumped.

Not forward or backward but straight up. His hands found a stalactite hanging from the ceiling and his fingers locked around it with the grip of a creature that could hang from anything. His body swung upward and his feet found the rough surface of a crack in the ceiling that he couldn’t have seen with normal eyes. He pulled himself into the crack, wedged his body sideways and pushed off toward a vertical shaft he’d felt with his Primal Senses but hadn’t consciously registered until this exact second.

The whole sequence took maybe two seconds. From crouching at the water basin to hanging from the ceiling to launching himself into a shaft that led upward into another tunnel network. His Featherfall Reflex softened the landing when he hit the floor of the upper passage and his Kinetic Flux Runner had him at full speed before the echoes of the male gorilla’s frustrated roar finished bouncing off the walls below.

Thank you cat brain. Whatever that was, keep doing it.

The tunnel he was in now was smaller and rougher and angled steeply upward. After several minutes of climbing through it he saw something at the far end.

Light. Faint and grey and cold but real sunlight coming through a gap in the rock.

He reached the opening and pressed himself against the edge. It was small, barely wide enough for his shoulders. Beyond it was sky and air and a view that made his breath catch.

He was very high up. The mountain face dropped away below him in a sheer cliff that fell at least a hundred meters to the rocky slopes below. The forest spread out to the south and west in an endless dark green carpet and far to the northwest the trees thinned into the rocky terrain he’d been running through before entering the mountain.

But that wasn’t what caught his eye.

Far to the south, maybe fifteen or twenty kilometers away, the sky was on fire.

Something massive was flying in circles over a section of deep forest, breathing sheets of flame that lit up the canopy from above. Even from this distance the individual jets of fire were visible as bright orange lines against the darkening sky and the smoke columns rising from the burning trees were thick enough to look like grey pillars holding up the clouds.

The dragon. The one he’d seen circling the mountain peak on his tenth day in the forest. The one that had never left its mountain in all the weeks he’d been watching. It had left now and it was attacking something in the deep forest with a fury that turned the southern horizon into a wall of fire and smoke.

The dragon’s body was maybe thirty or forty meters long from what he could see at this distance. A wyvern was maybe ten to twelve meters. The dragon was only three times the size of a large wyvern but the power difference was something else entirely. The wyverns were big dangerous reptiles. This thing was a force of nature wearing a body. Each breath attack covered an area that would’ve taken a hundred wyverns working together to match.

Whatever is on the receiving end of that... I hope it did something to deserve it for this much fire. That looks like hell.

He didn’t know what was down there. Or why the dragon had left its mountain for the first time in weeks. But he looked at the devastation and the fire and the smoke. Then something inside him- some rational self-preservation instinct that existed alongside the cat reflexes, told him very clearly that he never wanted to be anywhere near that creature.

A crash from the tunnel behind him ended the sightseeing. The gorillas were smashing through the narrow passage he’d squeezed through, widening it with brute force because they were too big to fit.

He pushed away from the opening and moved to create some distance again.

I will kill you for this monkeys...

..

The last hour inside the mountain was the most absurd thing that had happened to him since arriving in this world and that was saying something considering his first week had included being chased by a leopard, nearly drowning in a river of blue slime and accidentally charming a wolf with his Love class skill and many more..

Every time he found an exit route the gorillas herded him away from it. Not by catching up but by positioning themselves in parallel tunnels and cutting off his angles. The female was faster and used the narrow passages sometimes. The male went through the wider ones and sometimes just made new ones by punching through walls.

Eren kept being pushed higher and deeper despite wanting to go down and out. He’d realized it around the thirty-minute mark when his Primal Senses level-up gave him better spatial awareness and every time he tried to circle back toward the cliff face exit the gorillas adjusted their pursuit to block the route.

Just before he was out of road, he stepped into open space.

[Congratulations! Your skill Absolute Equilibrium (Uncommon) levelled up]

-Level 3 > Level 4

[Congratulations! Your skill Observe (Uncommon) levelled up]

-Level 2 > Level 3

Two level-ups at the same time. The Observe upgrade hit him first and suddenly the massive cavern he’d stumbled into wasn’t just dark shapes and thermal signatures. His enhanced observation skill was feeding him details with a clarity that made his skin crawl.

He was standing in a feeding hall.

The cavern was enormous, easily fifty meters across and thirty meters high with rough walls that had been clawed and scratched by something with talons the size of his forearms.

The floor was covered in bones and dried blood and scraps of meat in various stages of decay. The smell was thick and rotten and his enhanced nose broke it down into components he didn’t want to identify.

And there were eyes!

Oh boy..

At least ten pairs of them, deep red and glowing faintly in the darkness like hot coals set into skulls the size of his entire body. The wyverns were arranged around the edges of the cavern, some lying on piles of bones and others crouched on ledges carved into the walls. Their wings were folded against their bodies and their long necks were curled so their heads rested on their forelegs.

Every single one of them was looking at him.

He’d entered through a crack in the wall between two larger tunnels, a passage that a wyvern would never fit through. The wyverns’ own entrance was a massive opening on the far side of the cavern, big enough for three of them to walk through side by side and through it Eren could see more tunnels, bigger ones, leading deeper into the mountain.

Eren activated Invisibility and his body vanished. Ten mana per second. Five seconds maximum. His Mana Pool started draining immediately and he took one careful step backward toward the crack he’d come through.

The wyverns kept looking at him.

Not at where he’d been standing. At where he was now. Their red eyes tracked his invisible body as he moved, following him step by step with the lazy predatory focus of something that could see him perfectly well despite the skill saying he shouldn’t be visible.

They can see through Invisibility. My Rare skill doesn’t work on them at all.

[Congratulations! Your skill Primal Senses (Uncommon) levelled up]

-Level 8 > Level 9

The level-up hit him like a wave of ice water through his head and genius plan’s failure...

FUCK!!

His awareness of the cavern tripled in an instant and he could feel every wyvern’s body heat, every heartbeat, every slight shift of their enormous weight on the bone-covered floor. He could feel the air currents from their breathing and the vibrations of the gorillas approaching through the tunnels behind him.

He could also feel, with perfect clarity, exactly how screwed he was.

The wyverns weren’t attacking but watching and that was the only good part of the situation. But he felt the truth in seconds.

Their watching was the the same way a cat watches a mouse that just walked into the middle of an open kitchen floor, not out of curiosity but out of the comfortable certainty that nothing the mouse does from this point forward matters.

His Invisibility ran out. His body flickered back into visibility and he stood there in a cavern full of wyverns, with two gorillas closing in from behind, no mana left, no energy left, his body covered in goblin filth and his stomach so empty it had stopped growling and started just hurting.

He needed to redirect the wyverns’ attention from himself to the gorillas. He needed to do it without getting killed by either group. He needed to find a safe place to sleep in a mountain full of apex predators. And he needed to do all of this in the next few minutes or he was going to collapse and never wake up.

How did I think this was going to work? What part of "run into a wyvern nest and hope for the best" sounded like a plan?

Fu*k me...