Well stuff like the Rotweed and Broher having one eye. They're incidental to the situation in a way that describing the location of the Red star cult isn't. One common thing you see in Narrative games (or even trad games played in a looser more narrative way), is that the players can throw this stuff out there but there's a line they can't cross, understanding that line is necessary.
Also incidental stuff does get reincorporated. So I, a player, mentioned Broher having one eye. The GM runs with that and say he lost it at the battle of Habershon, again maybe this is just color. Several sessions later the GM needs to reference a battle and he thinks about what's been established, oh Habershon. Then the players need someone who knows about that battle, oh Broher. The color then becomes relevant and it seems like the fiction has a life of its own (which I'm assuming we all regularly experience)