Kathryn Mark is the daughter of Jason Blood and Glenda Mark. Her birth was not planned by either of her parents, but by a more malevolent party, the demon Etrigan, who had sinister intent for her existence.
When the longtime friendship of Jason and Glenda became intimate, the malicious Etrigan perforated Blood's contraceptive magically while caged inside his mortal form.  What appeared to be a mere act of spite was really the start of a long, ambitious scheme to unleash great evil on Earth. As months passed, Etrigan's power over Blood increased, forcing Blood to push Glenda away from him for her own protection. In Hell Etrigan conducted his own intimate affairs, copulating with Lady Smegma in the Sunless Sea, merging his seed with the essence of the Great Shadow. 
After nine months had passed, at Gotham City Hospital, Glenda gave birth to her daughter. Before she even had time to decide on a name, Etrigan burst into her room and stole the newborn from her arms, whisking her away to the ruins of a desecrated church. Here he secreted her away under a cloaking spell before returning to Hell to begin the binding ritual to transfer his own demonic son into the infant's mortal body.  Enlisting the help of Merlin and Tommy Monaghan, Blood found his child and removed her from the pentacle before the ritual was completed, sacrificing himself by becoming the new vessel.  Hitman saw Glenda and the newly named Kathryn safely home. Once home, Glenda was about to take Jason's advice about removing him from their lives, by burning his photograph. She didn't go through with it, promising herself she'd do it tomorrow. 
- Potential names for Glenda's daughter were Sarah, Annie, Katie, Claire, Pattie, Jayne and Helen. If she were a boy, her name would have been Harold.
- 3 Appearances of Kathryn Mark (New Earth)
- 1 Images featuring Kathryn Mark (New Earth)
- Quotations by or about Kathryn Mark (New Earth)
- Character Gallery: Kathryn Mark (New Earth)
|The Demon supporting cast|
This character has been an ally or antagonist to either The Demon Etrigan or his counterpart Jason Blood in any of their various incarnations.