False Modesty
On more than one occasion, Four will boast on her modest behaviors, dress and her want of things. But this is merely a facade; an act to make her feel superior to her more eccentric and better looking sisters.
With subtle and minor suggestions from those around her -- including Decadus -- Four will happily accept gifts and lavish herself in expensive clothes and jewelry. Often times commenting how it would go to waste or how she must keep up appearances for humanity who looks up to the Intoner's.
This couples closely with her sexuality, where again, she boasts on her lack of intercourse and her efforts to remain pure until true love comes. A mere guise to help her feel superior, and of higher quality than her older -- and younger -- sister's. She has extreme sexual desires just as any Intoner does, but instead, she nurses them in private.
Well, private to the extent that she forces Decadus to hear her, and refuse him to partake.