General Arryn demands the Chief of the Frontier, Jon, to send help. Jon releases his Insect Army to mark the invaders. Jon represents B-cells. They mediate response and produce antibodies. The Insects are the antibodies and their jobs are tagging the pathogens for phagocytes and prevents the pathogen from infecting more cells.
Arya's task right now is to kill any organisms that are affected by the toxic and mucus of the Monsters. She acts as Cytotoxic T-cells. They are responsible for finding cells that express a particular antigen and destroying them.
The Insects mark the Joffrey and Ramsay for The Guardians. Now The Guardians will kill the Monsters.