Haro, a stray Hokkaido dog discovered injured and malnourished near a Beika mortuary, narrowly avoided being struck by a vehicle before rescue and adoption. Visible cuts and bruises marked his prior hardships as a stray.

His name originated from a positive reaction to specific music, though it also holds an unrelated in-universe association. After adoption, Haro lived in an apartment, requiring routine feeding, hydration, and veterinary visits for vaccinations.

Initially wary, Haro exhibited nervousness around unfamiliar people. Under Kazami Yuuya's temporary care, he hesitated to eat or relieve himself, potentially unsettled by scents like other animals. Guidance from Haro's owner recommended calming techniques like maintaining eye contact and gentle petting beneath the chin, methods effective during Kazami's care.

Haro gradually built trust, initiating play by voluntarily approaching Kazami with a ball. Training sessions focused on foundational commands like running, fetching, and obstacle navigation, where Haro participated enthusiastically, showing increasing comfort with human companionship.

Daily neighborhood walks with his owner provided respite, cementing their bond and showcasing Haro's transition from a vulnerable stray to an integrated, content companion.