- 6: Mentioned as 'your mother' by Daphne Blake.
- 16: With her own made up backstory, Kathryn dressed as Aphrodite for Professor Pericles, planning and succeeding to murder Ed Machine.
- 17: Danny Darrow was killed by an earthquake made by her.
- 27: Dressed as Janet Nettles, Kathryn (still hired by Pericles) tried to murder Scooby-Doo but failed. Her real name was revealed.
- 33: As Modor Bjorkland, Kathryn spied on the gang but did no damage. She informed Pericles of their plans for a ski trip.
- 36: While trying to kill the gang, she killed Natasha Fenk by accident.
- 37: For Pericles (again), Kathryn dressed as the ghost of Abigail Gluck.
- 38: During one of Pericles' evil schemes, she befriended Judy Reeves.
- 39: Using a special tracking device, she managed to find out where the gang had hidden the disc. She failed to steal it because of the ghost of her daughter April Hezna
- 41: She can be seen hidden in the audience at the play.
- 42: She got her sister to dress as an alien.
- 43: She helped create the Skull Cattle, and was devastated when they were thrown into the ocean.
- 44: With a knife, she carved a message in a dying dogs (Nova's) body, thus killing the Nova.
- 45: Daphne asked Francilee Jackson if she was Kathryn. She wasn't.
- 46: She had a crush on the Dandy Highwayman, tried to get captured but failed, therefore getting slapped by Pericles.
- 47: She controlled the Skell-o-bots in another one of Pericles' schemes.
- 48: Daphne asked Fred Jones in the Sitting room why Kathyrn wasn't there...because she was too evil.
- 49: She dressed as Janet Nettles' friend, having really killed her. Shortly after, Kathryn killed Nettles and fled into the jungle.
- 50: She made a racist comment on Cassidy Williams and killed some slaves.
- 51: She accompanied her fellow villains through various universes.
- 52: She killed Ricky for the Evil Entity, who spared her. She was killed in a Galaxy explosion, and picked April up from school in Post-nibiru.
- Episode 6 (mentioned)
- Episode 16
- Episode 17 (mentioned)
- Episode 27
- Episode 33
- Episode 36
- Episode 37
- Episode 38
- Episode 39
- Episode 41
- Episode 42 (mentioned)
- Episode 43
- Episode 44 (mentioned)
- Episode 45 (mentioned)
- Episode 46
- Episode 47 (flashback)
- Episode 48 (mentioned)
- Episode 49
- Episode 50
- Episode 51
- Episode 52 (death in Pre-nibiru, alive in Post-nibiru
- Ed Machine in Episode 16 (helped plan the death only)
- Danny Darrow in Episode 17
- Natasha Fenk in Episoe 36
- Nova in Episode 44
- Janet Nettles in Episode 49
- Nan Blake, Dorothy Blake, Daisy Blake, Delilah Blake and Dawn Blake in Episode 50
- Ricky Owens in Episode 52
In Season 1, their relation was only mentioned in Episode 16. In Episode 30, while standing up against Professor Pericles, April claimed her mother made the wrong choice in life. Upon being murdered by him, Kathryn said horrible things about her daughter. Much later, April's ghost returned to stop Kathryn from stealing the disk pieces, in which Kathryn insanely impled she doesn't love April and wanted to kill her, although she was already dead. Hurt and angry, April left her mother. In Post-nibiru, they appear to get along as Kathryn picked April up from school and hugged her.
- Unknown to April, Kathryn named April that only because that was her birth month. It is presumed there is a different story in Post-nibiru.