There was nothing outside the door. He didn't see anyone or any shadows.

The worker, who was swarthy, immediately turned deathly pale. He kept his eyes fixed on the deep and quiet alley as if he was attacked by the Petrification Curse in an instant.

"Who is knocking at the door?"

Companions standing behind him didn't know what had happened. They thought it was the butler of Prince Yu's Mansion.

"No... no one is knocking at the door... ...