@zanonyn
Again, it was not me that stated that demons were animals that evolved to prey on humans. It was stated in universe as the truth ( now, if it is the truth or not, we still have to see ). I just pointed out that this made that demons were bound by the same evolutionary pressures than animals in our world, with mana being thrown to the mix ( in the end, no matter the nature of mana, if you drop it in the evolutionary cauldron, it is just a tool for survival like fangs or brains ). Sure, that doesn't ensure that the results will be the same than RL animals, but it is quite a given that similar evolutionary pressures will tend to produce similar results ... and if they are diferent, there must be a evolutionary reason for it ( even if the reason is just dumb luck )
So, let's look at what we know about demons, taking what the chars say as true.
First, they aren't timeless or even immortal: they come to be and can die. Second, while they don't start at the same level of mana, they can ( and will ) increase their mana potential through experience, something important as they tend to live long. Third, their society ( like you say ) doesn't care for the young and we already saw one of them just tossed into the human world. Fourth, their society is ruled by a hen pecking order and the strongest rule over the weaker ( while there is no direct statement on how demons actually gauge themselves against eachother, it can't be just by mana levels, because there are diferent spells and skills. Say, sure Aura would win most of the fights with her spell, but she still neded to activate it and it is conceivable that someone could take her out before she could activate it ... so there would actually be some fights to gauge whose skillset ( not only mana ) would be stronger ) . Fifth, they are honest to a fault about their mana levels ( again, I'm assuming that everyone is saying the truth )
So, let's assume this society exists and ask ourselves: is this societal structure with this beings evolutionary stable? In other words, could a rogue individual in this society with a diferent "strategy" ( not necessarily a conscious strategy, just making things through life ) do better than a average individual that abides by those rules or not ? Because , if there is, the individuals that use it will do better inside that societal structure and their "strategy" will start spreading ( because demons learn
).
And the answer is "there is" ( and probably there is more than one ): specifically, can go by a very simple "fake weakness when pressed against a stronger demon, flaunt your power when pressed against a inferior one, smash any upstart that shows promisse of taking you out". And why? Because of the second point, the pecking order can't be static if demons are coming to be ( in other words, if demon appear and get skills, some of them are bound to eventually surpass already existing demons , even if by a fluke on their experience gain ) and you'll eventually been to assert your newfound power on someone that once was your superior. That means that, on the other hand someone that is in top of the pecking order will need to get a eye on upstarts, because you really don't want them taking on you ... and one way to do so is to kick them down while they are still managable.
To avoid that, any upstart demon would need to hinge on the first fact we pointed out : the fact that demons have a potentially finite ammount of time to live. That means you have to set priorities in using your time and that some stuff, while doable, will simply not be worth the time doing it compared with other stuff. So, a possible way of not being curbstomped by a still powerful demon that fears your grown is to play weak until you are confident you can decisively beat them would be making a fight between you and them simply not worth their time. And because fights spend mana even if temporarily ( stated in universe in multiple chapters, including this one ) and time, you only really want to fight battles you really need to, so fighting battles that you would lose and battles that are not worth the cost in mana in time, like fighting a demon visibly weaker than you, would be avoided.
So, a strategy of " play weak with the strong, strong with the weak and nip in the bud any threat you can detect" would be superior to the rather naive "strong rule weak " in all the possible situations a demon could find himself. If weaker, avoidng curbstomp battle by playing possum would make the stronger ones shrug and move on, if strong there would be less fights to do, because only powerful enough demons would actually challenge you. Also, in that very perilous time where a demon would be in the cusp of ascending above other, both sides would be better by folling this strategy than by assuming that everyone was being honest at all times.
In other words, the proposed society is not evolutionary stable if all the premisses above are true. it would only take a less than fully honest demon to flip it to something else if given time. So , something of what was assumed above is not true: either ( or and ) they are not the product of evolution, they are timeless, they can't change their power with time, their society is not a in a hen pecking order system or they are not as stringently honest about mana levels as stated. While all of them are not set on stone, the ones with more chances of not being true are them being the product of evolution and them being fully honest with their mana levels at all times.
Note that nothing that I said above has
anything to do with them having anything resembling a human like society: note that specifically I don't even assume demons have parents at all ( they appear not to have, since they don't know the concept of father )and that they have pride or not ( in fact, it is the other way around: pride is a evolutionary consequence as much as anything else, and it would need to content with less prideful aproaches evolutionarily ) ) . I just pointed out that the proposed society would not be evolutionary stable with what we know about demons. Sure, our knowledge might ( sure is ) incomplete or maybe even false, but, if we assume that everything is like it was printed, there is something that doesn't add up. What doesn't add up? I don't know, but if I had to pick one, it would be that they are a animal that evolved to prey on humans. Their skillset and society would fit far better a designed creature to hunt and destroy humans ... more a hound than a wolf.
@Fushiginiku
You misunderstood what I said about strong rule weak, something that it was hinted when I talked about hen pecking order ( what hen pecks on what hen ). I meant that, in the demon society you rule above the weaker than you and obey to the ones stronger than you. In other words, exactly what you say when you compare with wolves , not a group of strong treating all the others at the same low level. And I agree that model is probably is what the author was pointing to.
The issue that I take is that this societal model in a population with a potentially finite lifespan and drainable ( and potentially refillable ) mana pool ( both of those are confirmed in text ) would not lead to demons being honest with their mana levels at all points if it is just shaped by evolutionary forces ( like it is stated in text, again ). I explain why above, but to resume, a less than honest demon in a society structured like that would have a undue advantage above the average demon of a comparable skill to his that was honest to fault ... so more demons would start acting like that with time until the advantage of being less than honest ran down due to the increasing number of liars in the population.
So, there is something fishy in all this issue IMHO. What? I don't know.