belief can influence us. little more complicate than just say something will hurt faeries, so definitely will - not really want go too deep in how work. but.
some faery can tolerate iron.
some hate same tree type that others love.
some can lie like no tomorrow.
this why faery rules, safety, and defense not so clear cut: what hurt some really could bring others, and what some unable handle, others have no problem.
put very very simple - if we feel something should happen or be true, then may become true. if feel should not, then may lose grip on us.
that may, or may not, be influence by others around us. also not conscious process, so some may never feel like this apply. not even sure if can say this much universal, but still true regardless that not all have same rules.
iron
with variation in faery lore, can be hard figure out just how protect self when need. iron most popular repellent, but how and why?disclaimer: this include some modern interpretations, and personal faery experiences - neither which always exactly folklore accurate.
not say that any one rule wholly right, just show how much variance can come from one simple rule. any faery can have "iron rules" in any combination.
first, need figure out what iron means here:
- only cold worked iron do anything.
- only relatively pure iron do anything, but can make any form, and work in any way.
- any metal with iron alloy have effect.
- only things that call by name iron have effect - steel do not, but dietary iron do.
and now need figure out those rules, how and why work!
- iron work by scare back to home world.
- iron work by injure or kill faery.
- iron entirely repel from area or person that hold.
- iron work because people imbue with energy and magic against faery.
- iron work because repel general evil, and later, faery fall under "evil".
- iron work because something in physical structure harm faery.
as well as:
- iron only do anything if faery physically touch.
- iron prevent faery from cross doorway and other border.
- just point iron in direction is enough.
and even:
- iron work because this ancient lore. might not be same now, but still able do harm.
- iron did work in past, but not same now. no effect.
- situational... only sometimes work! say, only iron that take certain form can hurt, or only if properly imbue with magic. if someone's faith in iron falter, so will effect.
you can see why rules and safety get complicate, yes? even in just one rule, can have so much difference that almost foolish just say "iron always work."
in welsh lore
(not complete.)
in welsh gwragedd annwn stories, human man through some means marry gwraig annwn - faery that live under lake. for this reason sometimes translate as lady or ladies of the lake, not relate to arthurian legends.all have common theme that if wife ever hit three times - or just once with iron - she will return home.
what "hit" means can vary: from actual abuse, to tap on shoulder when not expect, to even bump on accident.
always end same: she leave human world, through carelessness or cruelty. in some, husband try follow only to drown.
in one story about llyn y dywarchen, husband and wife plan on sell horse at fair. this horse refuse cooperate with bridle, so husband ask for wife's help. horse seem calm down, and nearly able put bridle on - but suddenly make fuss again. in anger, husband throw bridle at horse. but wife also chase down, and this bridle have iron bit.
as hit, she disappear in instant, not allow walk earth anymore - only her home in annwn. of course, she find loophole to bring comfort - she can visit husband and kids from small island on water's surface, and do until they die.