Josephine serves as the Arashiyama family's pet dog, physically resembling a Japanese raccoon dog (tanuki). She primarily interacts with family members, notably acting as the sole friend of Ayumu Arashiyama, Hotori's father. In the anime adaptation, Josephine displays a distinctive speech pattern ending sentences with the verbal tic "poko". Her typical pet behaviors include residing in a doghouse on the family property.

One incident involved Josephine placing an active sparkler inside her doghouse among flammable materials, causing the structure to catch fire. This event initially confused the Arashiyama siblings, who mistakenly believed the main family home had burned down. Beyond this incident, Josephine occasionally appears in standalone segments between anime chapters, sometimes accompanied by unrelated quotes.

Her narrative role remains consistently that of a family pet without significant development or expanded background across official media, including spin-offs, OVAs, or other extended formats.