Maruko Fujimura serves as a supporting character within the narrative and belongs to the Fujimura family, which comprises her father Tonio Fujimura and her sister Hatoko "Petoko" Fujimura. She displays a cheerful, friendly demeanor, frequently engaging with her peer group and showing consistent eagerness to assist others in need. Kindness and optimism define her personality, allowing her to maintain a positive attitude even when confronting personal challenges.

She holds the distinctive empathic ability "petopeto," enabling her to connect with and experience others' emotions. This power fosters deeper understanding and emotional support during difficult situations, though its intensity occasionally overwhelms her, requiring boundaries between aiding others and prioritizing self-care.

Her background involves navigating personal hardships with resilience, never compromising her core positivity. As part of the Fujimura household, she interacts within a family dynamic that includes her half-youkai sister Petoko. Her relationships center on camaraderie and emotional support, reinforcing themes of empathy throughout her engagements.