Why don't demons possess children until after puberty?

Question

In my world's magic system there is the otherworld. It is a many layered realm that is made from the memories of the land, the animals and the people. Some spirit worlds fade away if their people have gone or the land has changed too much. These spirit worlds can be accessed by mages, who can form their power to do low magic. Think mind tricks, animal manipulation, scrying, minor environmental manipulation (telekinesis, sparks), alchemy,...

Spirit worlds are however inhabited by demons. They can be bound and drained to produce magical artefacts, or called into a body (either the mage's own one for a while, or into a permanent host). While the demon does decay in the real world, it allows one to use high magic. Teleportation, fireballs, shields, liquifying humans, you name it.

Demons usually represent aspects of their spirit world (this means emotions for humans, the lands elementals are an entirely different breed). They tend to seek freedom and will live out their desires to the fullest to gain more power in the otherworld. To gain freedom they try to possess the mages or break their bonds.

However, while magic abilities manifest from birth on, demons don't care for mages until they are older. Why?

Answer 1

It's hard enough to fit yourself into the limited psyche of an adult human, now you want us to squeeze into children? A demon's gotta breathe, I tell ya!

You will note that demons also decline to possess the mentally feeble.
But we love nothing better than a nice deranged, depraved adult mind. All those phobias, ambitions, lusts and greed make for such nice cuddly, cozy nooks to camp out in.

It's all a question of housing quality and space.

Answer 2

Demons can't possess refrigerators. Or rotting peaches. The list of things they can't possess is long, it's much easier to list those things which can be possessed. The list is just one item long: human beings.

Why?

Because some deity or another created humanity to be a vehicle for spirits. It's not clear why or how that works, but it does. Otherwise spirits can only have the most limited of interactions with the physical universe. Chimps might have 99% of their DNA in common with us (and be much stronger, more agile meat-suits), but they just don't work.

But whatever the mechanism is in the human body that allows that soul to drive around in it, whatever the details are for how it works... there's this one other gotcha. No children. Perhaps the deity made it that way deliberately, or it's a side effect of some other function. Your story need not explain it unless you've decided that it's critical there be an explanation. Details can be included without explaining them... perhaps the exact age varies from child to child, or is exactly on their thirteenth birthday (for a legalistic sort of magic). The change may manifest with a perfect correlation to puberty, or it could be imperfect (short of doing large-scale demon possession experiments, how would you know that 1 in 1000 prepubescent children can be possessed, or that 1 in 400 post-pubescent remain unpossessable for years afterward?).

Answer 3

The onset of puberty and the consequent sexual drive greatly increase the quality of the juice which can be extracted by the subjects.

Think of the difference between unfermented grape juice and wine.

Answer 4

Growth is inhibited by the presence of the demon. If you possess the children, people will notice that they do not grow and that they never hit puberty. (This is owing to the demon's unusual attachment to time.)

It is growth, not aging, though. Adults age normally.

Answer 5

As children enter puberty, lascivious desires weaken their resistance to possession.

It's something succubi and incubi have known for a long time: you can't possess those whose greatest temptations and darkest desires are so innocent as to almost be considered wholesome. When someone grows older and begins to see the world in new eyes, the inrush of temptations and internal emotional turmoil makes it significantly easier for demons to possess the body.

Answer 6

The spirit is housed in the brain

If you ask if someone has a benevolent spirit, they talk about your actions and thoughts. However, these come from the mind, which is housed in the brain. So it follows that spirit is housed in the brain.

Children are still developing. Language, object permanence, sight depth, raw understanding or body movement. That and a lot more is all still being created and modified to have a fully functioning person. After puberty the most important development has been done. This allows for the demon to most effectively move into the brain. Of course some demonic powers allow for more knowledge, power and understanding that the demon already had, but it is still very much linked to the body and brain. So a good basis of a person after puberty makes a demon able to really fulfill it's own desires and gain more power.

Answer 7

Your setting may not be conducive to this but:

It’s a diplomacy thing.

There are other entities living in the Spirit Worlds which, by common agreement, are not in an active state of war with your demons. Some are neutral, some are hostile to demons, others are like demons but want any excuse to thin the competition. Humans too, will hunt demons when they find them but they haven’t yet reached the state of ‘holy crusade’ either. Nobody wants a war, but there can’t really be peace. So they exist in a state of compromise (for the time being).

One of these compromises is that demons can’t unleash their full capabilities against a child. To do so risks breaking the fragile peace and causing chaotic war not seen since insert reference to suitable apocalyptic event here. Any demon that breaks this rule will be hunted and destroyed not only by their enemies but also by other demons in an attempt to maintain some facade of inter-species peace.

Only when a child reaches some value of maturity (could be age, puberty or some other mystical event) is a demon allowed to possess a human. Of course, the rules are a lot fuzzier on helping the little humans. And they tend to be much easier to possess if you’ve already been riding along in their head for a decade and a half, so demons skirt the inter-species rules by providing magical assistance to child mages, befriending them, helping them, until the right age is reached and the demon can step into a pre-prepared (and in some cases willing) vessel. Technically they followed all the rules, so nobody can spark the magical equivalent of an international incident, and the demon still gets a nice powerful human host.

Of course, it might backfire in the demon’s faces, but what is life without a little risk?

Answer 8

Demons are like vampires: they have to be invited in.

Adults can do that. They may be smarter than children, but adults are still pretty easy to swindle, and merely being a mage doesn't make you any less susceptible to accepting bad deals or being taken in by cons. Children, on the other hand, while even easier to trick, are fundamentally incapable of giving consent. Not merely legally, but neurologically--it's not merely a matter of not understanding what they are about to do when giving a demon permission to enter, it's a matter of not even being capable of understanding. Any appearance of consent is thus invalid, and the demon cannot enter.

Answer 9

A demon's ability to affect the world is proportional to the ability of the host to affect the world.

It's not so much puberty itself, as the various restrictions humans put on human children that make it harder for a demon who possessed a child to be able to do things.

If a demon possess a host, they likely want to be incognito for a bit until they fully check their powers are working as intended, and able to do so away from unpossessed humans who might call for authorities to investigate the possession, or to attempt an exorcism themselves.

What's that? This one's host has to be back home by 7:00 p.m.? Given education during the day, that's basically an hour at most to work if they bolt after a 5:30 dinner, which might stand out.

Well, maybe I'll get a drink to help calm my host's nerves and get more power usage out of that - wait, my host can't get a drink at the local bar?

This is very annoying - clearly something must be done about these parental units, but I can't confirm my host is powerful enough to take on these parental units. And it's likely the authorities would investigate us taking them down, so I'd need to get my host to leave and live in a forest, I guess, and potentially buy things with the leftover funds the parental units had.

Wait, my host would get caught trying to use a car and likely pulled over by the authorities?

Well, okay, I'll leave as a result, and live sort of out of town - people won't be suspicious if I keep a low profile, and just eat a lot of forest mushrooms.

Solo children also stand out, and would likely be interrupted by authorities or parental units of other children for being alone and away from others.

Much like these above restrictions, a solo child host can't usually walk around disaster scenes unnoticed, and would likely be picked out by parents or authorities trying to help, even if they're trying to do mischief at a carnival or a major transport location.

At best, this starts to get suspicious, and makes it harder to get away with actual mischief.

You might want to adjust some of these specific rules based on the society in question, but in general - the demons in question have a lot more leeway with what they can do that's demonic if they're older and given more privileges, especially when their host isn't part of a demonic conspiracy through a whole family all in on the possession. And even then, you have societal concerns to worry about

Better to wait for them to have more curfews lifted and more permissions provided and expected, and just work from there.

Answer 10

Because let's face it, not even demons want to go put up with humans undergoing puberty

See, the thing with demons is that their goal is to extend their power within their realm, which is why they want to make use of potent mages. The problem is that possessing them works best when the mage's and demon's objectives (i.e. hunger for power etc.) are roughly aligned.

That just doesn't work so well with children up to and throughout puberty because whatever they are going for is so much more erratic. Only after completion of puberty do humans get a proper grasp on longer-term thinking and planning. Before that, demons can't really effectively advance their own schemes because their hosts just can't be relied on to pursue a single goal for a reasonably long period of time.

As a result, with demons being pragmatic, they prefer not to put up with all that flightyness of childrens' minds and rather go for targets that offer better chances to effectively be manipulated into aligning with a demon's agenda.

Answer 11

[Demons] tend to seek freedom and will live out their desires to the fullest to gain more power in the otherworld.

Children, as a rule, don't have a lot of freedom. They have parents, teachers, chaperones, babysitters. They don't tend to have money, property, equipment, or resources. They don't have the benefit of years to work on their skills, build their reputation, or acquire temporal power. Other people tend to be dismissive of them, if not hostile to them.

Demons inhabit people to increase their scope to act on the world. Why would they inhabit people who don't have that scope?

Answer 12

Children are "innocent"

We've all heard people say that. "Children are little angels, innocent of wrong doing! Their souls go straight to heaven!"

In your universe, its literally true! Childrens souls are repositories of everything that is goodness. Its only as time goes on that the harshness of life makes them darker and more morally complex.

Puberty is the cut off point for pure untainted innocence. Perfect place for it to happen too as sex and rebellion come into play. It's a spiritual human flaw that humans cant have sex and still be innocent. Oh well.

Answer 13

The society in which mages exists has societal controls on children + demon combinations. For example, there wouldn't be too many communities where children would be allowed to arbitrarily acquire and use flamethrowers, just because they can, doesn't mean society would allow it.

With this in mind,

scenario 1: Perhaps the community/society doesn't teach / enable / license children to effectively bind, control and maximise the connection with demons.

scenario 2: As mages mature, their real world influence / access is greater. Demonic society is familiar with this concept so demons prefer hosts that have distinguished themselves in some way - maybe a coming-of-age initiation ceremony.

Answer 14

Because demons hate having to buy new clothes

(This is obviously a not too serious answer)

If demons possessed still growing human beings, they would also need to buy new clothes to adapt to the varying size.
This would force the demons to set apart their fulfilling evil activities for more mundane and boring activities, like visiting shops to buy new dresses and try clothes/shoes in order to buy the right size.
In order to avoid such scenario, all demons prefer possessing full grown human beings, which allows them to have an already established wardrobe and, when the dresses become too old, they at least already know the right size of their body, so they can buy online the clothing they need.

Of course they still could lose/gain weight, but this could be avoided (even with some magic), while the growth because of age could not be avoided.

Answer 15

They can't possess the innocent. Trying to do so can do irreparable damage to the demon. So to be safe the demons avoid possessing kids who may not be mature enough to understand the nature of their actions.

Answer 16

Contrary to what some have mentioned here, I do insist on it has only to do with sexuality*.

In fact, being sexually immoral (well, one may argue about morality here and there, but demons are chiefly a religious thing, and religion often has - or should have - ideas about sexuality that are contrary to progressive openness and whatnot) is said to be the key event in losing the supreme being's protection as their creature (confer B'reshit / Genesis, as in "the fall of mankind"), which is essential for the so-called demons (evil spirits, or whatnot) to be allowed to possess someone.

In accordance with this, it is also important to consider that there is nothing physical in children not being possessed - this limitation is purely dogmatical, i.e. a question of what is permitted for demons and what is not.

* To be more precise, it has to be with sin - it is just that moral offenses related to sexuality are way more common vices than it would be for a non-possessed kid to e.g. kill their parents intentionally (even for "culpable" reasons). Should such thing happen, though, it would almost definitely predispose them to the possibility of becoming possessed.

Answer 17

The Harry Potter-inspired version: children are magically protected by the love of their parents, this protection disappears at 17 yo puberty.

Answer 18

Demons are powered by gametes

The demons in your setting require the host's gametes, or reproductive cells, in order to sustain themselves for any length of time. Since children do not start producing these until after puberty starts, demons cannot sustain themselves for long inside a human child.

Of course, this also means that any adult hosting a demon will also be infertile.

Answer 19

Transactions and contracts. The demons expend something and gain something in return. When interacting in this capacity with humans, the child is still in an incomplete form and therefore they have a harder time sticking to them. So the demon would need to expend additional resources to accomplish their goals and so the transaction ends up in their loss. So over time they have learned that if they want to have a good chance of getting a good return on their investment they should only deal with adults. Exceptions will arise and never forget that rituals and the like can be used to prepare proper vessels of any age.

Summons can be considered much like phone calls, the other side has to answer before anything can happen and the demons have very good Caller ID.

Answer 20

They could - sometimes they do - but they cannot do magic in a childs body. Not even low magic - none at all. So even if they are stuck in a child, they can not "act out" until after puberty. Call it brain chemistry, call it hormones, blame it on godly protection - whatever - it simply does not work.

And what sane demon want's to be buried in a 14y old craving ice cream, fearing to get fat, having to deal with unclean skin and emotional outbreaks because the classmates obviously ignored the new haircut and all that while being forced to study basic writing and being scolded from parents that saw the growing blush because this other juvenil person may have beamed a tiny look towards your host's bodies direction...

Plot-Twist: the demons themself do not want this knowledge to get out because it would be a valid (although cruel for the child) way to lock a demon aways for a decade.

If drugs get invented that stay off puberty, you could have a demon prison for a longer time.

Answer 21

They can possess children, however, there are better targets

Even while magical abilities manifest from birth, you have to train and study hard to grow into a remarkable mage.

The strongest mages were usually taken into academies while they were infants to undergo very strict training till they reached their current power - or even better, were born into these academies so their training essentially starts at day 1.

The process is very time consuming a gradual process of perfecting skills and training so their mind/bodies/meridians can handle/channel/generate more Energy/Mana/Qi - even the most talented individuals take a many years to hold their own against the strongest mages out there. Let alone actually confront and defeat them.

Demons have their power limited by their hosts - if they try to use too much, the hosts explodes and the demon is at least severely injured. Most of the time they would try to possess at least get an adult - preferably a hosts with more affinity so they can use more power.

Nothing stops them from possessing children, however, given that this is not advantageous, they usually only do that if they are desperate and have to hide somewhere - perhaps to recover.

Puberty is just the "barely acceptable" threshold - this allows them to use some power - at least enough to search for someone better. Demons would like to possess strong mages, not random muggles and certainly not children, unless they have to.

Answer 22

We all know how children are so much better at things like learning language. Whatever languages you encounter enough as a child you'll grow up speaking effortlessly. Languages learned later are much harder and few people will ever be truly fluent. This is an actual change in the brain.

Demonic possession has nothing to do with puberty, it's that demons can't possess a brain that is still in the rapid learning phase.

Answer 23

Priests are too vigilant with children

When people are possessed by demons, the treatment given is to take them to a priest and have them exorcised. This is "game over" for the demon.

Demons try to hide the fact that they've possessed someone for most of the time, and they do a good job of it. In order to detect that someone's been possessed, it both helps to be closely familiar with the individual to notice that they've changed, and it helps to be a priest, because they're the experts on demons.

In this world, children go to schools run by the Church, until they hit puberty at which stage they're old enough to work full-time. Going to school means that priests spend several hours a day with them, when they're in relatively small groups. If a demon possesses them, the priest would notice immediately. By contrast, a priest would only see an adult once a week, and even then in a large gathering of hundreds of people.

So it's not that they can't possess a pre-pubescent child, it's just that it wouldn't make sense to do so.

Answer 24

Every human has magic. Some learn to use it in complex and deliberate ways and so become mages. Others only do what comes naturally.

Natural magic, like everything in nature, is a product of evolution and is devoted to survival and reproduction.

Children's natural magic is entirely focused on survival. This manifests as rapid healing, general luck, and immunity to possession.

At puberty, some of that magic is redirected to reproduction. Creating a soul is a big deal, and the body needs to be ready. The resources needed for that get pulled away from survival, leaving the 'adult' vulnerable to possession.

(Optionally, the trigger might not be puberty per se but first sex, in which case virgins would have other interesting magical properties.)

(This does suggest that a prepubescent trained mage might be vulerable, having hacked their own body to redirect magic from safety to deliberate action. That's probably too rare to worry about, though.)

Answer 25

Because children's feelings and minds are way too instable

Prepubescent and pubescent children experience highly swaying emotions, and are mainly led by emotions (as opposed to rationality)

This creates an highly unstable environment that demons have trouble controlling. One misstep, and the demon could get swallowed by the intense emotions.

Compared to that, adults that mainly run on rationality / have the ability to control their emotions, are way more stable and less dangerous hosts