Beelzebub, also known as the "Queen of Flies," is a powerful demon and a central figure in the demon realm. She holds the prestigious position of the Minister of Agriculture, a role she earned through exemplary performance, having risen from humble origins to the nobility. Despite her high status and immense power, Beelzebub has a very approachable and eccentric personality. She is kind, protective, and deeply loyal to her friends, often acting as a caring older sister or a doting aunt figure rather than a fearsome lord of demons.

Physically, Beelzebub has the appearance of a young woman around seventeen years of age, but her true age is over three thousand years old, making her roughly ten times older than the immortal witch Azusa Aizawa. Her demonic features include dark skin, striking silver hair, horns, a tail, and large insect-like wings that allow her to fly. She also possesses the unique ability to transform into a small fly, a form she often uses for espionage or simply to relax incognito.

Beelzebub is first introduced in the story as an antagonist of sorts. The elf Halkara, believing she had made Beelzebub gravely ill with her energy drink, the Nutri-Spirit, seeks refuge from her at Azusa's home. However, it is soon revealed that Beelzebub was not angry; the drink had simply given her so much energy that she accidentally overworked herself into exhaustion. She had been secretly present in Azusa's house the entire time, disguised as a fly, simply out of curiosity. Following a comedic duel where Beelzebub is accidentally defeated by running into Azusa's magical barrier, she becomes a close and regular ally of Azusa and her growing family.

Her motivations are generally simple and focused on a comfortable, hard-working life. She takes her role as Minister of Agriculture seriously and is dedicated to her duties. Outside of work, her primary goal is to forge a genuine friendship with Azusa and settle their interrupted duel in a friendly manner. She is also drawn to the peaceful and chaotic warmth of Azusa's household, expressing a desire to be included in their fun activities and even jokingly asking to adopt the slime-girl twins, Falfa and Shalsha, whom she adores.

Through her interactions with Azusa and the others, Beelzebub shows a softer side, abandoning any pretense of being a scary demon. She is a reliable and powerful ally in adventures, helping to capture troublesome Blue Dragons and providing political support from the demon realm. Her character sees little internal conflict as she is already comfortable with who she is; her development is more about integrating into this new circle of friends and indulging in previously unfamiliar experiences like hot spring baths and spicy food, which she loves.

In terms of abilities, Beelzebub is exceptionally powerful, even among the high-ranking elite of the demon realm. She is a master of demonic magic, including powerful summoning spells, which she has even taught to Azusa. Her combat prowess is formidable; she can easily trap multiple high-level creatures, such as five Blue Dragons, in magical circles. Since becoming a minister, she has further strengthened her body through rigorous training and can even manifest immense bat-like wings in addition to her insect ones. Her skills are not just limited to combat, however, as she possesses excellent knowledge of agriculture, a vast network of political and social contacts, and is considered one of the strongest demons of her time.