Karen was a mechanic and a part-time detective, whose involvement in our grand story started with her working in a small private detective agency in Boston with Peter Steele and Frank Jones.
Following the Case of Corbitt's House and the death of Frank Jones, she was forced to leave her favorite cat with her ex-boyfriend and flee from Boston to Arkham together with Peter Steele and Ivan Zygzytsia. On the road there they encountered and trapped the Eater of Sins and got involved in a search for stolen Witch Trials papers in Arkham.
During her stay in Arkham, Karen began hearing voices and experiencing weird visions. Later she found evidence that she was a distant ascendant of Kesiah Mason, the legendary witch who was burned alive during the Witch Trials.
In January 1925 she was among the friends of Jackson Elias who arrived to New York on his behest and witnessed Jackson's brutal murder in room 410 of Chelsea Hotel by the Cult of the Bloody Tongue.
According to the last will of Jackson Elias, Karen, along with Peter Steele, Ivan Zygzytsia and Shaun Lanetti was hired by Carlton Ramsey, the late Jackson's lawyer and executor of estate, to track down the Carlysle Expedition, as well as investigate the murder of Elias.
She bravely faced the knife-wielding cultists and hungry zombies alike, and survived the many-headed screaming horror of Chacota in the basement of Ju-ju House. That was where she found the strange three-faced Mask of Hayama.
Upon putting the mask on, she found herself on a grey shore, where she was greeted by Nodens. The hoary Elder God invited her into His chariot and rode with her across the sea and the sky. He gave unto Karen the power to smite the servants of Nyarlathotep and returned her to the waking world.
After the vanquishing of the Cult of the Bloody Tongue in New York, she traveled to London with Peter Steele and Ivan Zygzytsia, following the path of Carlysle Expedition. During her stay in London, she got acquainted with a New Scotland Yard inspector James Barrington and managed to convince him (at least somewhat, initially) that the Penhew Foundation and it's director Edward Gavigan were somehow behind the series of murders (dubbed Egyptian Murders) that were going on in London.
After an encounter with Miles and Bertha Shipley, she, along with Peter and Ivan, was captured by The Brotherhood of the Black Pharaoh and taken to Misr House to be sacrificed. The saving party of James Barrington, Mickey Mahoney and Yaleesha Essam arrived a little too late for Karen, as she seized the opportunity to use that power granted to her and engulfed both Edward Gavigan and herself in ethereal flames that turned them both into ashes, to the approval of both Nodens and old Kesiah Mason.