It's a fantasy role-playing game.

DM: You are Vax Vax'ildan, a half-elf rogue . You are the member of the famous group of adventurers. Previously, Grog collapses the passageway behind them as they dash through one of the arches. Running ahead of the collapsing stone tunnel, the party finally comes in view of an opening to the surface.
DM: You guys are maybe 150 feet or so from the edge, so you're toward the side of the city. The tower is in the very center, so it's maybe half a mile from you. It's not half a mile; half a mile is ridiculous. No, it's maybe 400 feet from you?
Player: Am I able to tell, if this is a giant, domed-in city, are we in a little corner of it, or are we coming up somewhere mid-range?
DM: If you were to look out at it from an overhead circle view, from the center, you're a little ways near the edge.
Player: Okay, so not right against it?
DM: Yeah, you're about 150 feet from the edge.
Player: How close are the nearest of the gloomstalkers flying around?
DM: At this point, looking up, you see about three or four that are maybe 70 or 80 feet above you. But they're doing passes. They're not being stationary and they're constantly circling through. As you glance up and look and nudge away, you can see their yellow eyes piercing from their black, lightless form. Their wings, as they expand and shift, you can see that faint glance, the beams of their vision, scanning across the rooftops. They're all very intent on seeing what's going through the city.
Player: And do I see any motherfuckers on the streets?
DM: Make a perception check.
Player: Yeah. Use the Colville die, the meteorite. It's pretty good. It's 29.
DM: 29? Okay. Couple things. One, as you glance through the streets, you can see now why the top chamber of Thomara was so bereft of undead. They've all been moved topside. You see, glancing through the bits of street that you have in visual range, maybe 35 to 40 dwarven undead that are wandering through open spaces, mixing with the various soldiers from battles long past, when Thar Amphala still existed in the Shadowfell. You've encountered those undead already. You also glance around past the gloomstalkers as you're keeping an eye. As you're scanning through the crowds, you see something different: larger, flying through the skies on the opposite end of the dome. It appears winged, with a tail, but porous, like a tattered sail or a ladder. A skeletal beast of long neck and tail makes a baneful circle over the city with burning green-blue eyes.
Player: Is it dragon-shaped?
DM: It's kind of dragon-shaped.
