WOW WOW WOW This is what you call worldbuilding -The Hanging City by Charlie N. Holmberg
Mankind is dwindling in a world where is hardly any water available. (due to a devastating war, environmental problems??? Too far in the past to be mentioned) On the arid land some small human settlements try to survive. Lark a young woman has fled those settlements and is now standing at the entrance to a large bridge that spans a deep and dark canyon and is the route towards the ruined city of the humans of old. But when she tries to cross the bridge she is captured by the mortal enemies of mankind the trolls who have build a city hanging under the bridge as a kind of giant waspsnest. Lark however has a secret weapon what made the Troll council decide to spare her. Also the trolls are hindered by the drought but as they can tap into the river they can survive as long as they can fight the monsters lurking in the canyon. But they cannot travel to other troll towns anymore. The trollis as is their own name for their species is a martial society but not that different from humans apa