Spooky facts:
Ougi's name (扇) is a combination of 戸 (Door) + 羽 (Wing) from Hanekawa (羽川).
Ougi means fan, which is a wordplay of introducing her as Araragi's fan but there is another word pronounced as Ougi which is fitting.
Ougi (奥義) can also mean mystery and is written with the Kanji for inner, esoteric (奥) and righteousness, justice (義).
I wonder how deep the Nisio rabbit-hole goes.