Bug City Express
Some thaumaturgists theorize that the metahuman mind is incapable of peering at something so simple as an insect for too long, lest it be drawn in. Some say that the bugs have always been out there, waiting for mana levels to rise again. And some say that it is the inherent instability of our own selves that created these beings. Regardless, insect spirits differ from other spirits in several important ways.
First, a summoned insect spirit experiences a phenomenon known as Evanescence. Their force drains away into the manasphere, and they lose power and eventually die. The only way for them to stop this is to be invested into a host: a living metahuman, whose soul is destroyed by the process. Sometimes the spirit is too strong and the body dissolves, leaving a ‘true form’: a normal, astral insect spirit that is immune to Evanescence. Sometimes the spirit and the body come to a stalemate, creating the horrific ‘hybrid form’, a dual-natured creature with a shattered mind but impressive physique. And sometimes the body resists, and you get a ‘flesh form’: retaining the host’s appearance, skills, and memories, and able to pass in metahuman society, but with the agendas and goals of a spirit bent on subverting us all. In any case, an insect spirit that has been invested into a host (no matter the form) can no longer be banished back to its home plane. Its form must be killed, at which point it is disrupted.
Secondly, insect spirits all possess a hive mind, even those that are solitary and not part of a traditional hive. They have a permanent mental connection to all the other insect spirits summoned by the same shaman or part of the same hive.
Thirdly, when a nymph spirit undergoes metamorphosis into a queen, the queen spirit gains the ability to gate in other spirits directly from the astral plane, negating the need for a shaman in the hive. This means that any queen who establishes a hive will begin rapidly converting all available bodies into hosts for her hive.
And finally, insect spirits are allergic to insecticide. Normal bug spray causes rashes and shrieking, and KE IV (designed specifically to fight these guys) eats away at their flesh and drives them totally bonkers.