Probably best to keep away from the clown and circus euphemisms for the moment though - don't want to make them any more terrifying for the kid then they probably already are
Probably what the real world needs when the demons actually
do rise and storm the upperworld is a whole lot of people utterly desensitised by everything from Wolfenstein and Doom to Buffy and True Blood. There'll be ones that don't run when they should do, but any that survive the first encounter will know what to do with a chainsaw, will get that grenade
just where it hurts in the maw of the vilest of beasts, will resist the incursions from below as easily as they resisted the regiments of invaders from space by shooting up at their bombing runs whilst occasionally hiding behind buildings.
Our youngsters will be the ones that prepare the landslides, the floods, and as a sideline divert Earth's own lifeblood to deal with the less troublesome enemies.
If I've got a vote for who gets the Spartan armour and the sniper rifles, I'm putting my friends' kids forward. But they'd be as bad as gremlins with levers. But maybe the OP's daughter... Yeah, I'd trust a DF player to do that. Although I'd probably check first to make sure my nicely-appointed room didn't have a mysterious hatch in the ceiling, first...