On one hand, if you send your characters on a quest, you always have a way to have a man come through a door with a gun in his hand. Particularly if your muse has bright, sparkly ideas.
On the other hand, once he comes through, he has to do something. Interact with the characters. And not through a potted exposition of who he is. . . .
Unless of course you can fit that in. I can imagine coming about the turn in the road to find -- oh -- a city of delicate filigree in gold, white gold, rose gold, etc and someone noticing the staring travelers to puff up like a bantam rooster and proclaim that he is pleased that they have found the city worthy of the tales, travelers come from all about to gawk. . . but not in this tale.
So I have to poke about with the ravens to consider their smarts and their liking for shiny things and persuade them to be a suitable menace, not too tough, not too easy. . . . and eventually they coughed up a way it could happen, and as I started to write it in the outline, they coughed up a better one, so that the first one could be foiled. . . ah the life of a writer, trying to make life difficult for characters.
Though they did end up plopping them in the labyrinth. How sweet of them. Now I just got to do the same thing for the labyrinth.