Guita Hebby Fantasia is a member of the Cleaners, specifically part of a sub-group known as Team Child. Her past remains largely unexplored, though it is known that she joined the organization and was assigned to this team led by the Cleaner Bro.

In terms of personality, Guita embodies the demeanor of a loud, touchy, and childish teenager. She often fails to grasp normal social cues, as demonstrated when she immediately asked the protagonist Rudo about his experience in "heaven," showing a blunt and unfiltered curiosity. Her speech pattern is notably slurred, and she becomes easily excitable, particularly when confronted with animals or monsters, cheerfully greeting a cockroach without any sense of disgust. This excitement is a core part of her character, reflecting a love for living things and a fascination with creatures typically seen as frightening. Her primary motivation appears to be simple and childlike, driven more by her immediate interests and the companionship of her team rather than any grand ambition.

Within the story, Guita serves as a member of the supporting cast among the Cleaners. She is often seen in the company of her teammates Bro and Dear, participating in daily life at the headquarters, attending events like welcoming parties, and being present during briefings on enemy threats. Her key relationships are therefore with the other members of Team Child, who function as her primary social group and caretakers. Despite her young age and lack of experience, she is a recognized force within the organization. Her lack of maturity and battle experience means she is often underestimated, even by her fellow Cleaners, who sometimes forget the sheer scale of her power. Her development is closely tied to learning to control and apply her abilities effectively in high-stakes situations, as seen when her team must rely on her to turn the tide of a difficult battle.

Guita's most defining feature is her notable ability, which stems from her Vital Instrument: her gray kaiju-themed onesie. This item allows her to transform into a giant, plush-bodied kaiju monster, a power that significantly increases her size and grants her immense destructive capabilities. In this form, her body becomes soft and cushion-like, allowing her to survive high falls and even dampen the impact for others who hold onto her. While she cannot fly, she can use her large frame to glide short distances. It has been implied that Guita can control the extent of her transformation, with her comrade Bro instructing her not to go beyond a certain size level, hinting that she can grow even larger than what she has typically shown and that there may be risks associated with pushing her power too far. This ability makes her a secret weapon of sorts, capable of facing massive trash beasts single-handedly, despite her childish nature and limited combat experience.