There are a few different kinds of weapons used in the fight against the Pashe-ki. One is the bow and arrow. It's the usual thing, except the arrow points are made of a special substance, the only substance that will pierce a Pashe-ki's scales. Which, is scientifically named Mercury I Veraem. This elemental combination, its name shortened to Veraem, is only found on Kellaria, the richest deposit being near Dragon Moon. It has the strangest properties. If it is touching something solid, it is harder than diamonds, but when it is suspended, like if it falls somehow, then it becomes a silvery liquid. (When the air molecules fully enclose it, the surface of the veraem allows the air molecules to penetrate. The air molecules expand the solid Veraem molecules, therefore turning it into a liquid. When the Liquid Veraem touches a solid again, the solid molecules penetrate into the substance, somewhat crystalizing it into a solid form again). The founding of this element was what inspired the Earthlings (probably just Kivessa) to create some sort of weapon that uses these strange properties to an advantage. That's how Kivessa and Eli'akim came up with the idea of a gun-like weapon that uses veraem with electromagnetism. In experiments, the gun tended to be more powerful, and the liquid veraem went through the scales easier than the solid veraem. That's because of the inertia of the liquid, and when it impacts, it becomes solid, therefore becoming a pointy object while entering flesh. This weapon was found to be much more easier to handle than the bow and arrows or swords or daggers, but the trick was how were they going to get more batteries? They were banned from ever returning earth. But, they did anyway, and devised a way to have the gun run off a simple watch battery. The gun comes in many forms, a form like the wrist/arm thing in the Fathom comics, a small handgun, or a large main weapon gun.
Most people use two weapons, like a bow and a dagger, or a sword and a dagger. The wrist/arm attachment not only gives more protection, it doesn't get in the way, therefore they can have three weapons.