Okay, so here's a scenario: The hero (heroine) is struggling against a monsterous creature that has been attacking a city (let's name it Monde for kicks). The various humans are sick of this and decides to help the hero/heroine. They begin to raid gun stores, Lowes, the Monde History Museum and a medieval fair for all weapons they can get their hands on. So, this little army of...say...100 un-trained men and women who are armed with everything from a simple axe or hammer, to a chainsaw, to shotguns and rifles, etc. They charge the creature. It's insane, yes. I'm having a little trouble trying to figure that out myself. I mean, what would drive a bunch of un-trained civillians to grab whatever they can get their hands on to charge a monster that's currently overpowering the hero/heroine? What would possess them to do something that's both insane and suicidal? How would you set this up?
I wouild set it up myself, instead of asking (again) for a consensus. The only Writing Issue here is, are you going to write it? You gain nothing by not thinking these ideas through for yourself.
I think you already have the foundation for what would make them fight this creature .. it's attacking their city isn't it? That would be enough to make every individual want to do something, but the one thing that could be holding them back at that point is doubt about whether or not his peers will join him. Find a way to handle that doubt.