Pre-script: this is a post about meta-thinking. Recognize a weapon by its purpose, not whether it's gun-shaped.
Anything you can use to defeat your enemy is a weapon. The environment, social rules, the law, words or silence, their own friends, time itself - all weapons. At least, weapons as and when the opportunity to use them as such arises.
A true warrior erases the distinction between warrior and scholar caste. All of Reality is a potential weapon, and wisdom & training is required to grasp things in such a wide scope. (P.S. As such, being a warrior is one way of training scholarship.) Truth is the deadliest.
Naturally artifacts specifically designed to be weapons are particularly good at defeating your enemies. However, even non-thinkers are aware of this. Even a mindless drone will work out that they need a bullet-proof vest if you shoot enough of their acquaintances. The attack draws forth the defence. The mind, then, becomes the ultimate weapon. If you can grasp more weapons in the mind than they can, then they are unable to defend themselves. You will always have an avenue of attack.
Further, artifacts cost money whereas the environment happens by itself. If you allow the world to grant you weapons, you don't need to desperately seize or hold manmade weapons. If offence is needed, offence will be provided. Opportunity is as boundless as time.
P.P.S. Yet another reason honourable cooperation is important. Perfect security is impossible. Anything man can make, man can unmake. Allegorically, be tamper-evident, not tamper-proof. If someone wishes to tamper with your property, convince them it's more profitable not to - and catch them if they're trying to scam you. Likewise, the death sentence is critical. If someone refuses to abjure deviance, they must be deviated right off the mortal coil.
Because the mind is the greatest weapon, it behooves the highest warriors to attack the mind directly. Destroy their ability to want to attack you. Make them underestimate you. Make them think you're not a threat. Make them think you don't exist. The fate of a true warrior's enemy is to drown in delusion.
They're stupid enough to want to be an enemy instead of a cooperator. Your mind is guaranteed to be superior to theirs. Accept this advantage, exploit it, and crush them when and however is convenient for you.
If "God" is a metaphor for Reality in the widest possible view, then the Alpha and Omega of weapons is piety. A truly sacrosanct zone will not be attacked. The profanity from which the conflict arises makes them weak, unable to defend against it. In a material sense, the sacrosanct security will not be tested at all, because its enemies cannot conceive of it as an opponent. Security cannot be perfect, but perhaps meta-security can be.