Robozo is an artificially created being resembling a large Frankenstein's monster, constructed long ago through alchemy by an ancestor of the vampire family to serve as their butler and protector.

Physically imposing with greenish skin, stitches, bolts on his neck, and a large frame, he possesses immense superhuman strength. Despite this monstrous appearance, Robozo exhibits a gentle, loyal, and somewhat childlike personality. He communicates non-verbally through gestures, expressions, and written notes, maintaining a quiet demeanor.

Deeply devoted to the vampire children Ru, Remi, and Ruka, Robozo acts as their primary caretaker and guardian. His duties encompass all household chores, including cooking, cleaning, and maintaining the castle grounds. He consistently prioritizes the children's safety and well-being, often going to great lengths to protect them or solve their problems.

His loyalty to the family is absolute. Robozo displays unwavering dedication to the young master, Ru, readily following instructions and providing steadfast support. He interacts with other household members like the ghostly maid Wanda and the bat-like Drac, assisting them and participating in their activities.

Robozo's existence is defined by his background as an alchemical creation. His purpose, established by his creator, is to serve and protect the vampire lineage. Throughout the series, he remains a constant, dependable presence, fulfilling his role with quiet diligence and deep affection for the children. His character maintains his core traits of loyalty, strength, gentleness, and devotion to duty without significant change or development.