An interesting phenomenon occurs from the use of distributed belief structures.  You can think of "distributed belief structures" as being like religion or folklore.  It is a structure of belief (a set of ideas, even) that is distributed across multiple believers.  As mentioned, the more affirmation an idea receives, the stronger it becomes, and the more real it is (but not necessarily more true).  So an idea believed by many people is generally more real than an idea believed by one person.
	We'll use an example of religion.  Let's say there is a society, and that society develops its own religion.  This society exists in a vacuum for now.  All of the people in this society believe in their religion.  To each of them, the ideas of their religion are reality.  Their god really does exist, the evidence exists as well.  Being a god, the god doesn't have to exist in the same way a person does.  What sort of life does the god live?  What does the god dream of?  Does the god eat food?  Does the god get cold during winter?  None of these questions may be answered by the religion, but they gradually get answered by the imagination of curious believers.  It's possible none of the questions get answered, if somehow all believers are unimaginative or lack curiousity.  Either way, these answers or non-answers further develop or restrict what sort of existence their god has.  The god is an idea, a shard of their beliefs - and so being, is subject to the imagination and understanding of all believers.
	Putting it more plainly:  gods are products of belief.  Gods can live like men, or dogs, or titans, or cosmic horrors - anything, according to belief.  This belief is rather like their lifeblood, or the metaphysical umbilical cord connecting idea to mind.  The greater the belief, the stronger the god.  The weaker the belief, the weaker the god.  And so, the method of killing a god or an idea becomes clear:  destroy all belief in it.  The simple method would probably be genocide, followed by record destruction, monument erasure, and maybe even destruction of the destroyers.  Well, I say "kill", but I'm talking about functional levels of existence; a "corpse" remains, forever, hidden in the unobserved.
	Now, let's surround the above society by other societies which have different beliefs.  The conflict of the beliefs only really apply where observers are confronted with the evidence of different beliefs.  Ideas gradually get exchanged, as normal, and belief systems shift to accomodate new ideas or to reject them.
	If the man-like god of one society attempted to walk into another society (outside the range of conviction of the believers), the attempt would fail.  The god exists only within the range of conviction, so it would require a number of believers to come with it in order to succeed.  But upon entering the range of conviction of opposing beliefs, the god would start to weaken.  If all of those believers suddenly died, the god would disappear (effectively, the reflection of the belief would vanish) and reappear at some other location with a more stable belief structure (pretty much always the home society, or whatever location they believe it might happen).  The god could potentially be killed, rather than the believers, but the possibility and process for that are really complicated because of all the precise beliefs involved.  If the god were actually killed or disempowered or captured or whatever, and the believers of that god affirmed the results according to their beliefs, and then they go home and convince the rest of the society, then the fate of that single reflection becomes the fate of the idea, as there would be no contradictory belief to fall back on.  
	Just one contradictory belief would be enough to save the god, although the god would be very weak then, and likely unable to be reflected in any sort of manifestation.  If this happened, there would effectively be a split of the original idea.  The majority affirmation would uphold the existence of the captured/killed/etc god, while a minority affirmation upholds the existence of the original god.  Those two beliefs contradict and reject each other, of course, and it's on such a scale that the majority basically "wins".  Now, if exactly half of the society changed their beliefs while the other half did not, the society would basically split in two and probably have a civil war.  Such a large, local rift would cause a conflict that can't compromise on its own.  The people would have to settle it somehow.  It is possible to have such a scenario result in a war of gods, as the believers' ideas get turned around to support their own affirmation by rejecting contradiction.  It's be a big mess, of course, and quite possibly destroy all nearby landscape, depending on what sort of powers the gods were affirmed into holding.  That kind of war of ideas actually has a clean metaphysical result, though, as it's plain to affirm the events unfolding in front of everyone's eyes.
	Of course, being gods, if you start changing the state of their existence in these ways, you can quickly get some crazy results within the range of conviction.  Like, if a god is controlling the rising of the sun, them dying means that the sun cannot rise again, creating an area of eternal night.  Outside observers would probably have to affirm such an anomaly into their own belief structures, because if everyone around it rejected that it's happening, whole chunk of conviction territory (the space that's covered in eternal night) would be banished to an alternate reality or plane of existence - one where their existence is affirmed in some way by distant observers.  This is pretty rare to happen, though, because most people will affirm bizarre events into their beliefs.  And that rarity eventually standardizes the occasional bizarre event, so they are even more readily affirmed - often by being pre-emptively explained by belief structures created by people who have already affirmed several bizarre events.
	Now, these kinds of distortions are only tied to physical spaces if the beliefs align just right.  Most of the time, they will be tied to the range of conviction of believers.  So, a person from the eternal darkness society, when they travel to another society, they would actuall appear to be cursed, as they slightly darken their surroundings as their personal reality rejects the sunlight around them.  Like so, when that person looks up, they will never see the sun, even if everybody around them sees it.  They won't recognize the shadows of others as being any stronger than moonlight could produce, and their vision will be somewhat impaired just like during the night.  Artificial light like fire still works fine for them, so they may carry a lantern or torch everywhere, which could cause other sorts of rumors about them other than simply suffering a pitiable curse.  They will probably make for poor burglars, as they don't understand that daylight exists for other people (they believe everyone is lying for some reason), so they would try to sneak in broad daylight.  Similar to dimming light near them, they also dim the heat of the sun, so on the hottest summer day, they might be seen wearing heavy clothing.  Maybe they'd be valued as portable air conditioners for field workers.  This 'curse' would get stronger, the more eternal night believers are in the same place.
	Now, if the society that the eternal night believer travels to rejects the effects of their beliefs (like, the society largely rejects the idea that darkness can follow a person, or that anomalies exist), then the effects shrink enough to where they can be excused as more believable phenomena.  No matter how much it's rejected, though, the eternal night believer  CANNOT see the sun or any sunlight, because that's the core of the belief they hold.  You could trick them into believing that your society has built a false sun that only shines for them, though.  But it's about those fundamentals.  The beliefs that are deeply held resist contradiction, and the path of easiest compromise is generally taken.  If every society got together and conspired to do so, they could effectively unify the world vision for even the eternal night believers, by tricking them on a massive scale.  Gaslighting is a legit warfare tactic, but it's complex and abstract enough to where it's extremely rare (there will be no vast conspiracy to save the eternal night believers).
	The situation isn't actually reversed if an outsider comes to visit the society of eternal night.  Because the outsider has already affirmed the existence of the darkness phenomenon, it is real to them, but it plays by the rules of however they affirmed it into their own belief structure.  If it's some wacky rule, like the zone of darkness is a bubble filled with poison gas and the ground covered in jewels, then they can hold their breath and pull out a bunch of jewels (that only those of similar belief could affirm the existence of).  Though that'd probably lead to a lot of invading rogues, and potentially the ability for these eternal night believers to gain resistance to poison within the society which believes they live in a big poison cloud.
	The flashy stuff has been covered, but there's a lot more subtle things going on with distributed belief structures.  Like folklore or oral history.  A lie told to children, if never corrected, becomes the truth for those children.  Correction can become impossible if it concerns the past, like a tale of an ancestor's heroic military career.  This sort of thing generally has little effect worth mentioning, but it leads into the next section.