Jillian (voiced by Maryke Hendrikse) is Dark Vegan's daughter. She doesn't approve of her father's evil ways. She made friends with Johnny and has helped him save his world twice. As of the Fourth Season she is living comfortably on Earth, having successfully integrated into its culture. In her second appearance, it is revealed that she has a crush on Johnny, also once she was having a sleepover at his house and accidentally kissed him.
Jillian has dark green hair unlike her father and mother. her hair is pulled back and up curling tightly. she has almond shaped blue eyes with bright blue eyeshadow with hot pink lipstick and sharp ears. she wears a hot pink shirt with a high collar and large white cuffs with dark purple pants with sharp white shoes. she also wears a red lei like necklase over it. she also has two headbands, a white one with yellow spikes pointing up and possible her tiara. her second one is pale pink and half way up her hair and might be a large hair tie.
- Jillian once had a boyfriend but was forced to break-up with him.
- It's hinted that she's possibly 13, because of when she said that if Johnny was 2 years older, she would kiss him.
- In the end of "Johnny in Outer Space" Johnny said that Jillian became the new leader of Vegandon, yet in Johnny X: The Final Ending (JX6-b) Dark Vegan claimed leadership.
- There is a lot unknown about her.
- She has a crush on Johnny.