I was idly wondering what would happen if Don Quixote entered a Far realm.
Then I wondered about the general case - how do faeries react to a character with Delusion? Somebody who sees the world according to a story more interesting than reality.
A Faerie with very high Cognizance might see his potential. But even this one would like to see his following increase for enhanced Vitality.
"Yep, you have Sancho already. So we provide you Dulcinea. But you have to pay for her, Sir Knight. Off to the tavern, to the puppet theater, to court! Get people involved with your ideas!
Best of course: find your Cervantes. The we can talk!"
Generally faeries are defined by whichever craftsman last altered their story, or by the stories being told by the population. If the person with the delusions is also a skilled craftsman they may well become pulled in to the stories they tell themself, but otherwise it really won't affect them (unless the deluded one is a persuasive speaker and a large number of people get pulled into sharing the delusions.)
The more disturbing thought is how many faerie Jews or faerie Saracens there might be running around based not on the real world but on the stories told about Jews and Saracens... racism and bigotry take a much nastier turn when they can manifest like this...
Yes, unfortunately fae will amplify stories, even the nasty ones. Clearly any SG can just avoid them.
I guess it could be an interesting, somewhat Cathartic story for some, for the characters to deal with some fae amplifying a "bad" story.
Could see a Faerie proving a Delusional person "right" by some trickery or what not, if it thought that the thing she believed was useful. After all, a delusion is only a delusion while it's not group consensus - if enough people start to believe that the delusional person is right, and they perhaps are mad, misinformed, or unable to see The Truth, then the collective perception shifts, perhaps makes it easier for a Faerie to manifest this or that if enough people think it OUGHT to exist, WANT to believe in it.
Depends on how cognizant the faerie and its role. The role will not change to bend to the delusion but beyond that they are no less capable of trying to capitalize on a person's delusion than anyone else.