In my scenario the world is being invaded by magical beings which quickly overwhelm our militaries because the way our realities interact:
- Our physical weapons have none or nearly no effect
- Our protection methods are similarly ineffective
The way my heroes eventually manage to turn the tide is by realizing that humans produce an aura that allows us to affect the invaders. For example:
- A simple melee weapon will carry our aura while it is being wielded and is thus capable of harming the invaders. However anything thrown or shot will lose the aura immediately.
- Materials will have their resilience against enemy attacks significantly increased when worn as armor. Now, even after our heroes create several generations of improved armors there would still be some damage getting through.
- Eventually they learn how to generate this aura artificially and turn it into projectile or energy weapons, even grenades
The problem is: I'm not quite sure why our non-military heroes are able to successfully exploit this situation and eventually defeat the enemy but the world's armies could not.
- Lack of attention - Our civilian heroes only had to contend with marginal opposition before gaining enough advances to even the playing field.
- Field density - A human's aura can only saturate so much matter. Enough to permeate personal equipment of a few kg but not enough for a few tons of tank/jet/battleship.
- Concentration - Military campaigns focus on fewer but larger scale engagements resulting in fast, heavy losses. Whereas the heroes are faced with far more sparsely distributed eradication forces.
Is this "plausible/realistic"? Anyone got something I missed?