Episode 028| Back Door

???

It didn't follow.

That last claw had cut empty air, and the Instance had given two words: "unexpected." Then it drew the claw back, its eyes dropped, and it stood in silence six meters off.

Lika understood what the posture meant.

It was waiting for him.

---

He hadn't finished reading the message in his head, the one that said the past him had written this.

Native to the Instance. Kaiyuan 925/3/11. Signature L.K.S._Core.

Across these thousand-odd years he had written a great many things — so many he couldn't even recall how many notebooks he'd filled. But he knew one thing for certain: every critical system he had ever built, he left a back door in — seven of them across his whole life.

It had been that way from the first day he ever touched a high-tier command.

What a writer fears most isn't someone else cracking the thing — it's finishing it and then forgetting how to get back in himself. So in every important system he left one door only he knew about.

He looked at the thing across from him.

If it was something he had written, then he should have a back door into it.

---

It moved again.

This time it didn't walk. It slid — a ripple of scales along its lower body shoving the whole frame forward four meters, leaving two.

Lika's Triggerer sense of direction spiked into the red.

[The contact target · motion detected]
[Speed: 1.8 m/s (walking) → 7.4 m/s (lunge)]
[Estimated time to contact: 0.27 s]

0.27 seconds.

This time Lika didn't retreat.

There was no time to — that last time, when his body had moved for him, he knew it hadn't been his own reaction; he suspected there was another command inside the Instance helping him, and whether he could use it a second time, he didn't know.

He changed his approach.

To the processing speed of the brain-chip interface, 0.27 seconds was enough to run the whole chain of inference.

He closed his eyes for a moment.

Not in surrender. He pulled the sense of direction all the way back in and looked inward.

[Triggerer · internal viewpoint activated]
[Target: signature analysis of the current environment]
[Scope: residual traces of the contact target]

The Instance gave him a message that surprised even him.

[Warning: request exceeds Triggerer authorization]
[Downgraded to internal observation mode]
[Privilege: READONLY]

READONLY.

He couldn't modify anything, couldn't run a command anymore. But he could read — he could see every step the contact target had just taken, every data signature it had left in the Instance.

Like looking at a page that had been quietly altered.

The marks of the alteration were right there.

That whole arc of the claw coming down was laid open.

[Rewrite action · parsing signature...]
[Executor: the contact target]
[Privilege used: render priority MAX]
[Base command: terrain_overwrite()]
[Parameter source: Instance root / /trial/contact/01.lks]

---

Instance root.

The contact target's attack wasn't generated by the thing itself. It was read out of an .lks module sitting in the Instance root.

It was executing something.

It was only the executor.

Something connected in Lika's head.

If the contact target was written by the past him, and its attack was read out of the Instance root —

take the bet: the Instance root might also be written by the past him.

He wasn't sure. But if it was, every important root directory he'd ever built, he left a back door in.

Its claw rose again.

Lika read the tells 0.4 seconds before the swing — the slight drop of the shoulder blade, the claw's center of gravity pulling back, the Instance's compute allocation tilting —

This time he didn't dodge.

He watched it swing.

At the instant the claw came down, his internal viewpoint showed him something.

[Instance root · hidden node detected]
[Node name: /dev/null (auto-ignored)]
[Detection reason: anomalous path naming · non-business node]
[Note: path is skipped by every read channel in the Instance]

/dev/null.

Every engineer knows that path. Anything written into it vanishes completely.

Every automatic read channel in the Instance skipped it — meaning the Instance itself would never touch it.

But what Lika had just started wasn't an automatic channel. It was the hidden-node detector of the Triggerer internal viewpoint — and that wasn't on the auto-ignore list.

So he saw it.

And it existed.

It was there. Sitting quietly in the root directory.

Lika's habit — when he wrote code and left a back door, he liked to put it somewhere the Instance couldn't scan but he himself would remember.

/dev/null was the one he used most.

---

The claw came down to two centimeters from his face.

The Instance flashed "unexpected" again.

He didn't dodge.

Its claw veered on its own, two centimeters.

In the instant the Instance showed Lika /dev/null, the Instance itself seemed to swerve the claw too.

It wasn't necessarily /dev/null answering him. It could be the contact target's own judgment, could be the design of the trial module, could be something else.

But the timing was too perfect.

Lika suspected — that path was alive.

---

Lika took a step back. His chest hammered — 158 beats per minute.

It was as if he'd found a back door. It was as if he'd touched it for a moment — and it had answered him.

【Ch. 028 End · Inside the Instance · Rift Memory Layer 1, Instance root】