Ishishi is one of twin boar characters serving as apprentices and close companions to the main protagonist. He and his twin Noshishi share nearly identical appearances, featuring brown fur, green shorts, and orange vests, occasionally accessorized with green scarves and blue umbrellas. The sole visual distinction is Noshishi's mole on the right cheek, absent on Ishishi.

Both twins display mischievous personalities aligned with their mentor, relishing sweet foods and playful troublemaking while maintaining steadfast loyalty during their travels. Individual traits receive minimal focus, though narrative moments occasionally highlight specific skills like Noshishi's drawing proficiency.

The twins' background is largely unexplored. The 1993 film adaptation briefly references Noshishi mentioning an oath forbidding their village return until becoming accomplished villains. This plot point remains unaddressed in later adaptations or series installments. Their origins and family history receive no elaboration in the main series or spin-offs.

Across the franchise—including television series, films, and OVAs—the twins function primarily as comic foils and unwavering supporters of the protagonist. Their roles prioritize collective camaraderie over individual arcs, with negligible evolution in personal goals or motivations. The sibling dynamic remains consistent: Ishishi is identified as the elder brother, Noshishi the younger, occasionally reflected through vocal pitch differences in animated portrayals. Later seasons and spin-off materials introduce no substantive deviations or backstory expansions.