Beezel is a demon living alone on a desolate island when first encountered. Initially characterized as lonely and prone to bullying, he attempts to drive others away through intimidation, using a statue of his father to frighten Unico. He explicitly demands isolation, ordering Unico off his territory.

His interactions with Unico reveal complexity. Beezel bargains for Unico's horn, agreeing to friendship only if Unico relinquishes it temporarily. During this time, Beezel engages in harmful play, riding Unico like a horse and whipping him with his tail despite the unicorn's clear discomfort. His careless actions directly cause Unico to fall into the ocean and nearly drown, triggered either by tricking Unico into eating extremely hot food (manga) or during roughhousing (film). This event marks a turning point.

Confronted with the consequences, Beezel undergoes change. Motivated by a deeply ingrained code of honor instilled by his father, he honors his bargain by swimming into the ocean to return the horn to the drowning Unico. This act revives Unico, enabling his transformation into an adult unicorn who rescues them both. Though Beezel verbally denies affection for Unico, his subsequent actions demonstrate genuine care.

His development culminates during the battle with Baron de Ghost. When Unico is gravely wounded and his horn shattered, Beezel willingly sacrifices the horn Unico had earlier gifted him as a farewell present. He uses it to replace Unico's broken horn, directly enabling Unico's revival and victory over the Baron. This selfless act, born from their bond, completes Beezel's arc from a solitary antagonist to a loyal friend capable of significant sacrifice.

After the battle, Beezel remains behind as the West Wind takes Unico away. He keeps the horn Unico gave him, a permanent symbol of their friendship and his personal transformation.