It's a fantasy role-playing game.

DM: You are Percival de Rolo, a human gunslinger . You are the member of the famous group of adventurers. Previously,  Some of them splintered off to try and acquire the goods that were taken from his store, however they apparently had already been stolen from the location they were being stored in, or been delivered already, they're uncertain as to what became of them. But they get the sense that it was probably best that they chose Gilmore over the gold, at first glance.
DM: I'd say it's about anywhere from 16 to 20 feet tall. It's two-story, but it's not extremely well-built.
Player: I'm going to try to get a vantage point where I can at least get where he's only three-quarters cover. So I suppose I'm going to head south down the alley to see if I can get a--
DM: Pushing to these guys?
Player: Yeah.
DM: Okay, so one-- You can get to about there if you want to.
Player: I can get a good look at him there.
DM: You can see, yeah. He'll have half-cover from there.
Player: Half-cover's fine. So, if I were to knock him prone, would he fall off the roof, or could I try and push him off the roof? These are my--
DM: For the wyvern, or for the rider?
Player: The wyvern.
DM: You can try. It's hard-pressed, he's sturdy on the side, knocking him prone might fall over onto the rooftop. Who knows if it'll slide or not. It's your call. What do you want to try?
Player: I'll try knocking him prone, and see if that does it.
DM: Okay!
