As with other versions of Psycho Jenny, this demon is shaped like a grinning woman's head with comparatively tiny arms and legs. She has wide, large eyes, a very large mouth. Her messy red hair circles her head and on her back is her torso with her chest and breasts. Her blue arms and legs are covered in red veins, on her wrists are two small spikes and her feet curl round at the top.
In her human form, Jenny is shown as a voluptuous woman with red hair, large yellow eyes with long eyelashes, and purple lips. Her appearance gives the impression that she has undergone excessive plastic surgery. Her clothing consists of a loosely fit gray work dress with exposed cleavage and no bra underneath. When showing her demonic side, her eyes become yellow and shadowed.
Psycho Jenny is a psychic powerhouse, able to wipe and restore memories in a instant as well as fly through the use of telekinetic levitation. Her psionic abilities are so powerful, she is able to warp reality around her and drive affected humans to suicide.
Psycho Jenny shows little personality, other than being fiercely devoted to Ryo and his well-being. She seemingly detests humanity and does not understand Ryo's obsession with Akira. However, she is not always violent to humans, as despite being annoyed with Moyuru Koda's offer to join Satan's army, she still let him in without harming him (Koda was a devilman, and thus half-human).
Psycho Jenny is shown to have exerted influence over Ryo's life since he was at an early age. She arrived at the seaside village in Japan to take away Ryo when he was a child.
Throughout Crybaby she serves as Ryo's secretary, assisting him in his apartment, serving food to Akira, and driving Ryo around. She does not play a significant role until the demon apocalypse occurs.
When Akira Fudo is attacked by Zennon and his subordinates, she stops the demons from killing Akira, stating that "it is His wish." She then senses the presence of Moyuru Koda, who is hiding and defects to the side of the demons. She perceives his decision as being human by nature.
As this occurs, Ryo is in Peru. Once Ryo regains his memories from the village and realizes his true identity as Satan, Jenny arrives to get him, knowing he must be aware of everything now.
During the final battle with humans, Jenny stands alongside Satan as they ride through the skies. She praises Satan for living alongside humans and understanding their weaknesses, as well as stating that she feared he would not return as he was "wounded in [the previous] battle".
Jenny uses her powerful psychic abilities to battle humans, but is ultimately killed when humans use special shields to block her psychic wave and impale her, leading to her death.
- Psycho Jenny's design is highly influenced by Yasushi Nirasawa's figure design, from the colour pallet, arm fins, and breasts on her back.
- During the opening cinematic, Jenny's jewel-patterned eye appears as one of the ink blot patterns alongside the other demons. It is the only pattern not to demonstrate perfect symmetry.