Ishishi is one of the twin boar companions to Zorori and the elder twin brother of Noshishi. The twins appear nearly identical, both possessing brown fur, green shorts, and an orange vest. They are occasionally seen wearing a green scarf and carrying blue umbrellas. The sole physical difference is a mole on Noshishi's right cheek, which Ishishi lacks.

Specific background details about the twins' origins are limited. A plot point in the 1993 film "Kaiketsu Zorori" shows both twins took an oath not to return to their home village until achieving success as villains.

Personality-wise, Ishishi shares traits with Noshishi and Zorori, including a love for sweet foods and engaging in mischief. The twins loyally accompany Zorori on his journeys. While Noshishi demonstrates proficiency in drawing, as seen when he reproduced a genie's likeness from memory in Season 1 Episode 8 of "Motto! Majime ni Fumajime Kaiketsu Zorori," no distinct skills or personality developments specific to Ishishi are detailed.

Their names derive from the Japanese word "Inoshishi," meaning "wild boar," with "Ishishi" representing one segment of the compound. In narratives, such as "Kaiketsu Zorori: Mamoru ze! Kyouryuu no Tamago," Ishishi consistently appears alongside Zorori and Noshishi as part of the central trio, undertaking collective missions like protecting dinosaur eggs. Throughout all appearances in films, seasons, OVAs, and other official media, Ishishi maintains a consistent role as a supporting figure within this core trio without individual character evolution or unique narrative arcs separate from the group.