The town shifted when they took their thirteenth step.
Not visibly. Not violently.
It was subtler than that.
The sound changed.
Eiran stopped immediately, raising his fist.
Behind him, boots scraped to a halt one by one. Breathing grew shallow. Even the priestess managed to suppress the tremor in her steps.
"What is it?" Karsen asked under his breath.
Eiran did not answer.
The echo was wrong.
Footsteps in NULL usually returned cleanly—stone to stone, angle to angle. Now, the sound lagged. Not delayed, but stretched, as if the ground was tasting the noise before giving it back.
Floor Eleven had finished observing movement.
Now it was observing intent.
The system window flickered.
OBSERVATION PHASE — UPDATED
PRIMARY VARIABLE: LEADERSHIP DISTRIBUTION
The words settled heavily in Eiran's chest.
Of course.
NULL always targeted efficiency.
"Leader…" one of the rookies whispered. "Why is it looking at you?"
Eiran lowered his hand slowly.
"Because I'm the easiest failure to scale," he said.
If he broke, the rest would follow.
They resumed walking, slower now. The buildings felt closer than before, alleys narrowing without actually changing shape. Windows reflected silhouettes that lagged half a second behind their owners.
Someone breathed when no one should have.
The swordsman flinched, hand tightening around his hilt.
"Don't," Eiran said immediately.
Too late.
The swordsman turned.
In the reflection of a cracked window, he saw himself standing alone—armor rusted, blade snapped, throat opened from ear to ear. The reflection smiled.
The scream was short.
The window burst outward, glass slicing the air as something pulled the swordsman in by the face. No enemy appeared. No system warning followed.
Just blood streaking down stone.
Then silence.
SYSTEM NOTICE: PARTY MEMBER LOST
NAME: UNREGISTERED
The rookies froze.
The priestess dropped to her knees, hands shaking violently.
Karsen stepped forward—then stopped when Eiran's hand clamped onto his shoulder.
"Don't look," Eiran said.
His voice was steady. Too steady.
Because inside, something was being measured.
The tower had learned how they reacted to sudden loss.
It had learned who hesitated. Who froze. Who looked back.
And most importantly—
It had learned that Eiran would not break formation to save someone already taken.
The system chimed again.
OBSERVATION COMPLETE
SECONDARY PHASE: IMITATION PREPARATION
The air grew colder.
From the alley where the swordsman had vanished, footsteps echoed back toward them.
Measured. Familiar.
Walking with the exact cadence of a man who used to be alive.
Eiran drew a slow breath.
"From this point on," he said quietly, "do not trust anything that walks like us."
Because NULL no longer needed to guess.
It had their shape now.