I can understand what you are saying here-Humans are physically weaker than most species. Just about everything else that lives on the planet has some form of natural defence-claws, teeth, physical size and strength, poison/fangs, armour plates, good senses to detect threats and so on. In that regards you are quite correct, a human who attempts to have a one on one fight against a bear is going to die....unless said bear gets so excited at the thought of a free meal it has a heart attack. On a purely physical level we should never have managed to avoid being eaten on a daily basis....but we changed the rules.
Human defences come from our intelligence, or given human history maybe I should say that our defence comes from the ability to invent and create tools. The tools that we can create provide us with the power to not only protect ourselves, but also to alter the enviroment we live in and control it to some degree. Control the enviroment and you also gain power as some species that would normally threaten you will not always be able (or want to) live there.
It is not weakness to rely on technology as such, it is our strength and without it we wouldn't be here. While the word technology often brings up a mental image of cars, computers and cell phones it is worth noting that technology simply means tools. A simple rock used to hit someone with is a tool, its also a bit of technology, it allows you to hit something harder than you could with your bare hands.....although against something like a bear you would need one hell of a large rock. That is part of what a tool does-it allows you to do things that normally you would be unable to do, or do things better than you could do unaided. Using the internet I can talk to someone 6000 miles away, and I quite often do, something I could not manage by shouting. This is power, it is just a different type of power than almost all other species on the planet have.
Of course while technology/tools are our greatest strength, they are also our greatest weakness when we rely on them so much we forget how to live without them. (I wonder how many people on this board would be able to go a month without using a computer or cell phone at all).
Power always comes at a price however, and tools are no exception. The price of us getting power from tools is twofold;
It can be too easy to get, and therefore misused or we fail to understand how dangerous using that tool can be-nuclear weapons being a prime example.
They can be used by almost anyone. As you pointed out a child could pick up and use a gun, and a trawl through police reports will tell you that happens more than we'd like in some places. That is the duel nature of power from tools-if you can use it so could someone else, which is why the military guards its armouries so well and tries not to let on exactly how their latest equipment works.
In simple terms whoever holds the tool has the power, as long as they choose to use that power. Having the power and using it are not the same thing. Just because I have a gun does not mean I have to use it....although a charging bear would tend to settle matters for most people...and even if I do decide to use it I don't have to shoot the bear, I could always fire into the air and hope the bear runs off at the noise. (If it doesn't I then have to hope I haven't just run out of bullets or the gun jambs, knowing my luck both would happen). Being able to choose how I use a tool involves being able to control it, and being able to control something means you have power over it. In the case of a monkey or baby with a gun the water is muddy here, since it could be argued that they are incapable of choosing to fire the gun and therefore have no real power as you said.(A monkey wouldn't know how to use a gun without being trained, in which case the monkey becomes a tool of the trainer. An untrained monkey, or a human baby, wouldn't be deliberatly firing the gun but doing so accidently, which again means they had no choice, therefore no control, therefore no power).
You also said it was a weakness to rely on others, again there is a small amount of truth in that, but this is over shadowed by the fact that humans are pre-programed to work in groups and rely on each other. This is the second way we survived. A single human with a stone axe is unlikely to be able to tackle a bear. But a group of humans armed the same way will make short work of it. True, there is a good chance that at least some of the humans are going to get hurt or killed, unless the know exactly what they are doing, so from the prospective of those individuals this is not a great stratagy. But from the view point of the species working together allows them to handle situations where an individual would fail, or finish a task in a shorter space of time. From an invididuals view point groups are a good thing too. To start with instead of being a single target, you are just one of several potential targets-hence the odds of you being picked out by a potential predator are lower making you less likely to be attacked and, therefore, less likely to need to defend yourself. Even if you are attacked if the group has a strong bond (and human groups, or at least the smaller ones, tend to be very strong in this area) then you are more likely to have someone else turning up to help you defend yourself against an attacker.
Anyway, the only part of this that is directly applicable to the thread is that about control and power. In order to have power over something you have to be able to choose to use that power-not for good or ill, just the ability to use it when you want to. Nilhus couldn't choose to use his power to drain life, he had to use his power to drain life-if he didn't he grew weaker, and as was mentioned in the game he would eventally have died regardless of what the Exile did-In fact he would have been dead even if the Exile had decided to stay away....That he had no control over his ability means that it did not make him powerful, in fact it means the opposite.
Needed repeating.