Mandrake is an extremely tall and lanky figure, frequently crouching to pass through doorways. Thick circular glasses obscure his expressions, and long, pointed ears are often mistaken for horns. He has short brown hair, contrasting with the long, dark purple style of his past musical career. He typically wears a purple robe and pants with a faint floral pattern over a white button-up shirt. When angered, he transforms dramatically: dark scales cover his body, claws emerge on his hands and feet, and dark smoke emanates from him. His eyes spark intensely, veins protrude on his forehead, and his clothing shifts to orange and black tones.

His personality is marked by extreme irritability and a strong preference for isolation, resenting any disturbances. Despite this volatile nature, he wields significant magical power within the household and possesses underlying good intentions. He was the first to show kindness to the adopted girl Earwig, revealing a capacity for warmth beneath his harsh exterior. He maintains a cynical relationship with his former bandmate, Bella Yaga, with no deeper friendship evident beyond their shared history.

Mandrake was the pianist for the rock band "Earwig" before its disbandment. Following the band's end, he became an author, though his books consistently receive poor reviews. He now resides with Bella Yaga, adopting Earwig primarily to provide Bella with an extra pair of hands for her witchcraft. His magical abilities include sealing all exits of their cottage to prevent escape, commanding small bat-like demons that deliver food or books, and transforming into a formidable fiery entity when provoked. This destructive transformation can ignite objects or damage the workshop.

Within the household, Mandrake enforces strict boundaries, especially guarding his private study with magical creatures. He reacts strongly to disruptions, whether Bella Yaga criticizes meals or Earwig provokes chaos. However, he demonstrates subtle care for Earwig, ensuring she receives meals and comforts like books via his demons. His connection to Earwig deepens when her biological mother, a former bandmate, unexpectedly reappears.