The Demon King rules the Demon World as Glenda's father. Though he presents an iron-fisted façade, his subjects genuinely love him due to his benevolent rulership. His marriage became strained when his wife abandoned the family, finding his personality overly goofy and irritating; this deeply impacted Glenda, who often scolds him over their conflicts.

He excessively dotes on Glenda, pampering and spoiling her to her annoyance. Obsessed with documenting her development, he maintains archives so vast they fill entire rooms with records of her life. Despite her frustration, he genuinely desires her happiness. His interactions include allowing the exiled demon Cube to massage him, unaware of Cube's banished status.

Physically, he possesses standard demonic features like horns and long ears adorned with earrings. His imposing role as ruler starkly contrasts with his domestic persona as a bumbling, non-threatening father figure.