Shishiku serves as a magical familiar partnered with the magical girl Yuri Inuwashi, representing Ishikawa Prefecture. Visually appearing as a small white dog with purple eyes, Shishiku's true nature is that of a miniature lion deity. This form enables Shishiku to transform into a larger Kaga lion during combat to support Yuri.

Shishiku possesses the ability to manipulate visibility, deliberately choosing to remain perceptible to ordinary humans instead of staying invisible like most familiars. This choice consistently attracts attention, particularly from young girls drawn to Shishiku's appealing appearance. Shishiku openly enjoys this attention and the resulting physical affection received in public.

In battle, Shishiku functions as Yuri's combat partner against the Magatsuhi, corrupted entities threatening Japan. The familiar's capacity to assume a larger, more powerful lion form proves strategically valuable in these confrontations. Shishiku's combat role is intrinsically linked to Yuri's activities safeguarding the region.