Karen first appeared in the second half of the episode, "Book of the Heart," and she is revealed as Jake's ex-fiancee, which dismays Heaven--who shared her first kiss with Jake. Karen turned heel later in the episode, when she murdered Dr. Fleming (a professor that Cheryl had a crush on), while he was inspecting important artifacts. Prior to Karen's heel turn, a passport with the name Kylie Devlin was found by Cheryl, who later informed Heaven about the discovery.
In the third and final two-part episode, "Book of the Shadow," Karen's true villainous role is revealed, as she is an assassin working for Heaven's father, Tasuke Sogo. After stabbing Sato, the evil Karen stabbed Jake and fought with Heaven before kidnapping Cheryl. When Heaven comes to, she receives a call from Karen, who insists on knowing the real location that she saw in the mirror. Heaven later encounters Karen, who still had Cheryl in her capture. Cheryl tosses Heaven her sword, who prepares for battle. Karen appears to have the upper hand, until Heaven pulls out a war fan, which had been given to her upon arrival by a native. However, Karen gets Heaven on the stone--about to spill her blood--only to be killed by Heaven when she summoned her sword, which goes through Karen's back.
- Stacy Keibler is more widely known for her wrestling career, and her status as a heel.