Sarah Cawkwell is no longer the only female novellist in the sausage party that is the Black Library but was for a very long time.
The running gag is that she is a hot, sexy (your mileage may vary), goth chick, and therefore not real. This is because the only women who go into a Games Workshop are the ones that fa/tg/uys dream up in their heads. She's actually a rather charismatic and regular looking human being, who has a blog, even though there are No Girls on the Internet. She wastes a lot of her time playing Morepigs, apparently.
She apparently researched Norse Sagas while writing Blood Raven, as the entire story is basically Valkia teaching her fellow Norscans a ritual torture exactly similar to the real-life "Blood Eagle" present in Norse sagas. This makes sense because the Warriors of Chaos are evil Chaos Vikings anyway, and because this ritual was already in Wulfrik. Also, Khorne apparently thought it up and gave it to the Norscans. It must be reiterated that this short story is named after the procedure detailed in the Norse sagas and NOT after a certain chapter of BAWLD AND FEWLISH SPEHSS MAREENS.
No one dares to make the obvious joke. NO ONE. As a corollary to the above, no one here is going to make the joke that her middle name is in fact a variation of "Swallows" or "Receives", because some jokes are too easy even for us. The obvious joke really is that her last name is missing an "s" somewhere in the middle, since a female author staffed at Black Library, who is also a decent author is enough to give any fa/tg/uy a raging chubby.