Oska's backstory: a cat nun on the move

This triggered a lot of worldbuilding! See the nuns of Paratti and also Sacred prostitution .
Long story short, Oska is an oracle in training, and what that means where she's from is that she has sex with supplicants asking for divinations. It's a religious thing. At home in the monastery, it's not strictly prostitution in the sex-for-money sense, but when nuns travel they sometimes use sex as part of their ambassadorship.
Being a prostitute in Malfa—that is, getting paid—might be Oska taking it upon herself to extend her role somewhat. Nobody disapproves or anything, it’s just that she's not having sex as part of a divinatory practice. See also "Vice" in Malfa.
The nuns are the keepers of a divine spring. One of the reasons Oska has been sent off to Malfa, is that there are rumours of another divine spring, a source of revealed secrets, somewhere “on the tip of the other continent.” Malfa is literally the tip of the other continent, so there you go. If this pans out, some of the Paratti nuns might even secede to found a new monastery.
Also, some revealed secrets mention something called “the Return.” It’s unknown what this means, and the current oracle isn’t interested. It isn’t even clear whether the Return would be a good thing or a bad thing. Perhaps someone should find out.