Paul felt the portal before he saw it. He could feel a deep thrum in his gut, regular and pulsating, like the heartbeat of a massive creature. He had stopped running when he first detected it, instantly moving into a crouch, dismissing his lights, and drawing upon [Hide in Shadows] and [Silent Movement] to cloak his passage.

As he traveled down the spiraling passage, the vibration became audible, and Paul could see a purple, flickering glow that appeared to sync with the thrum that shook his body. His steps slowed, creeping even more slowly toward the source of the light. The pulsating glow illuminated the cavern around him, and Paul stopped with a jolt as he noticed that the path he was following was well-worn, as if tread by many feet before him.

A notification for [Eye for Detail] ranking up to 3 made itself known, but Paul ignored it, crouching low to run his fingers along the ground. His fingers found a thick layer of dust, but underneath, the stone was worn smooth. He thought he heard an inquisitive chirp from Seymore and shook his head in annoyance.

Auditory hallucinations of Seymore, along with the eerie impression of the little lizard still riding on his shoulder, had become more frequent, and Paul was genuinely worried for his sanity. Shaking off the feeling, he considered the path before him and the mysterious source of the vibration and purple gleam where it seemed to lead. A sense of foreboding passed over him.

This is new.

The glow and sound grew brighter with each step until Paul rounded a corner, the tunnel opening into a cavern unlike any other he had encountered.

Despite his efforts to remain silent, Paul audibly gasped when he saw it.

It was in no way a natural formation. Eight smooth marble walls curved upwards from a stone floor to meet at a point forty meters above the ground. An undecipherable alien script covered the walls. Its silvery hue reflected the purple light emanating from the center of the room.

There, a stone archway rose, and between its arches danced a teeming emanation of incandescent purple light like an aurora stretched between two pillars of stone. The reverberation was overwhelming now, and Paul struggled to concentrate as he gaped at the impossible structure before him.

Paul skirted the edge of the room. There were no other exits. As he rounded the back of the arch, he half expected to see the purple light dancing on the opposite side as well, but instead, the back of the arch was the same material as the walls: Smooth, white marble.

What the fuck is this place?

Paul didn’t believe the Mantis Trolls built whatever this was. So far, he had seen nothing suggesting they could create something like this. He supposed they could have - he didn’t know anything about their society or technology level aside from their stone tools - but it seemed unlikely. Moreover, the room and arch had a distinct impression of age. Paul didn’t want to guess how old it was, but he felt that “centuries” was probably a conservative guess.

Paul circled the arch again, staring at the whirling amethyst maelstrom as he came to its front again. Then, hesitantly, he stepped closer to it and, employing the entire length of his spear, used the butt end to prod the amaranthine surface of the arch. It met no resistance, even when he pushed the spear past the point where it should have hit the marble back of the structure.

Bizarre, but somehow I’m not surprised.

It looked like a portal or doorway of some kind, so Paul was relatively non-plussed by the physics-defying nature of the arch.

Now that I can move lights with my mind, this is well within the bounds of strangeness I can accept, I suppose.

Emboldened, Paul stuck his spear further into the arch, its haft disappearing about halfway this time. He carefully removed it, then inspected the spear's length for any damage or change in temperature. Then, feeling emboldened, he reached out with a single finger.

It was not easy to do. Several times Paul extended his hand, finger a hair's breadth away from the swirling purple lights, only for him to yank it back.

C’mon, what’s the worst that can happen?

He immediately regretted the thought, his mind filled with images of energy pouring from the arch to disintegrate his body or the tip of his finger simply ceasing to exist.

This is reckless, Paul. There’s no need to experiment with this now. You can always come back later.

He turned to leave but stopped himself halfway through the motion.

If this is a door, this represents the best chance you’ve found to leave these god-forsaken caverns. Rip the bandaid off.

Sighing, Paul clenched his jaw, teeth grinding, and extended his shaking hand toward the arch’s surface. He closed his eyes, grit his teeth, and plunged his finger in.

The last thing he expected was a notification, but that is what flashed into his consciousness.

The message was wordier than any other he had seen before. The notification also didn’t fade away like others had. Instead, it demanded his attention even as he yanked his finger away from the arch as if he had been burned.

*Entrance to [Silent Stone Caverns Proving Grounds]*

*[Silent Stone Caverns Proving Grounds] last cleared 41 years, 126 days ago*

*Once entered, no other entities may enter the [Silent Stone Caverns Proving Grounds] for 1 month.*

*[Silent Stone Caverns Proving Grounds] is recommended for parties six entities of level 15 or higher.

Party entities detected: One. WARNING: the number of party members beneath the recommended threshold.

Entity level detected: ERROR, Level 0 is not a valid level.*

*WARNING: The interval since the last [Proving Grounds] clear has increased the difficulty above normal levels.*

*Would you like to enter the [Silent Stone Caverns Proving Grounds?] [Yes/No]*

It had been a long time in the caverns since a notification had surprised Paul as this one did. The sheer length of the message was completely new, as well as the fact that it persisted in his consciousness, seeming to wait for an answer to its question.

Paul’s first instinct was to immediately select the “No” option, but he quelled the impulse.

I can learn something here.

Taking a breath, Paul leaned on his spear and mentally dissected the message.

So it is some sort of doorway or portal. Evidently transporting whoever touches it a “Proving Ground,” whatever that is.

It seems like no one has activated it in decades. You would think that the Trolls would have stumbled upon it sometime during the past forty years. Maybe they can’t activate it or just choose not to. And if not the Trolls, does that mean other… people have come this way in the past? The worn stone leading to this area certainly lends itself to this theory.

The notification also mentions difficulty levels, which means that this “Proving Grounds” is some sort of a challenge - which makes sense due to its name. And if it's a challenge, it has some sort of designer. Someone - or something - placed this here.

For what purpose, or for who, Paul could not guess, so Paul moved on to the other part of the notification that worried him.

Am I supposed to have levels? And a party? So far, I’ve only gained ranks in skills.

On a whim, he whispered “Level up” into the empty cavern, then repeated it louder. To his complete lack of surprise, nothing happened. He shrugged; it was worth a try.

Finally, after taking a few minutes to commit the notification to memory, Paul said, “No.”

The notification vanished from his consciousness, and Paul again found himself staring at the whirling purple lights playing in the archway. He backed away slowly, taking small steps back into the exit, and did not turn around until the arch was entirely out of his view. Leaning one hand onto the cool rock of the tunnel wall, he sighed and tried to calm his chaotic mind. Fumbling with his pack’s straps, he removed it, sat down, and grabbed a waterskin.

His heart was still pounding hard from the experience. He had seen some strange things in the caverns, but the implications of this portal were profound, and Paul knew he would need some time to process them. He took a long swig from a waterskin and splashed a little on his face for good measure.

Mentally, he added the strange room and archway to his mental map. When he did, he felt a jolt of realization.

The path to the arch. I’ve seen this before.

Paul’s [Pathfinding] skill showed the maze of caverns that he had explored. With rising excitement, Paul focused on just the route that would lead from his resurrection spot to the archway. It was a relatively straightforward path, leading down a winding spiral.

I have seen this before - and I’ve been a fool.