The titular "ghost friend" and mascot of the series. She originally sets out to terrify Bob but ends up becoming his best friend, often hanging out at his house

The polite and dedicated main character. He is known for his signature yellow look, super strength, superhuman speed, and deep passion for cleaning. He works various jobs and lives with Susie but still somehow has a lot of time on his own despite working.

One of Bob's employers for whom he occasionally works as a cleaner or horticulturist. Ella is an employer of Bob, who is her gardener for her home, and she is the second woman to have a romantic interest for him.

Bibi's skin is colored medium purple, as are her clothes (which blend with her skin tone) and hair, which goes down to her upper back and has middle-part bangs. She is slim, and her left canine tooth is longer than average, which can be seen when she frowns or when her mouth opens while talking. Though she's soft on the inside.