Cirno continued knocking on the door, unable to detect and herself undetectable by the metaphysical entity known as Chaos due to her aura of idiocy, which prevented the embodiment of insanity, Chaos, from manifesting in her presence. As far as conceptual entities were concerned, the fairy and her fellow Touhou, Okuu, were spherical holes in the noosphere roughly 60 feet in diameter. 

"Heeeeeey!", Cirno knocked again, "Heeeey, open up! These guys wanna fight you!"