But how do they work ?
WELL, she gets her power from the life force of living beings around her, including plants which is the main sauce, other life forms only coming into the picture if there are no plants to brutally murder in the area.
So basically, the weapons will be made of this, and can be charged with it to be more destructive, etc.
This is also where her left eye being "on fire" comes in, which functions as a sort of amplifier thus making her faster/stronger and able to put more powah in attacks. Additionally, it allows her to regenerate her power supply faster than usual, thus causing plants and similar life forms to whither away and die around her. Not being the type to play around for no reason, she does this a lot while fighting things.