Hao Ren turned to look back in the direction everyone had come from. The path through the thick fog had vanished without a trace, leaving behind only a black, mirror-like surface rippling like water. The circular "mirror" seemed to have been drawn directly onto space, jutting abruptly out of the building. It stretched more than ten meters wide, its edges floating with countless fragmented black strips like dry-brushed oil paint. Curious, he reached out and touched it, but felt no solid surface at all. He leaned in and peered through it, only to find the path still lying on the other side. Heiserana tossed him an exasperated remark from behind. "If you want to go back, you can leave through one of these mirrors. Just follow the path straight ahead. You have marks on you, so you'll be fine as long as you don't wander into the fog. Every entrance where the Shadow Interlayer intersects with the real world is guarded by an Ancient One. Tell them who you are, and you'll be free to enter and leave this place. But don't bring anyone else in—your marks only work on you. Any outsider who enters the second layer of Shadow Space is doomed to die."
These mirror-like things were passages connecting the Shadow Fortress to the outside world, scattered throughout the city, with powerful Gatekeepers stationed at both ends. The one before Hao Ren was a relatively small one. In more heavily guarded parts of the city, there were larger entrances meant for transporting bulk supplies, but visitors could not simply set foot in those areas. Heiserana led everyone away from the platform. At the steps at its far end, they saw a towering ancient tree. Hao Ren couldn't help taking a few more looks at it. The tree was