Jiku, alternatively called Jikū Ajari, functions as a mentor in the narrative. Entrusted by Kujaku's father, he serves as Kujaku's master and trainer, acting as a guiding influence in his development. His characterization merges wisdom with personal flaws, including considerable knowledge alongside alcoholism and perversion. These traits mirror those of his apprentice, adding complexity to his role beyond conventional mentorship. The character appears consistently across adaptations: he maintains his position as Kujaku's master in the OVA series, and his foundational mentorship persists unchanged in live-action films. His narrative purpose focuses exclusively on guiding the protagonist and imparting knowledge. Jiku undergoes no significant development or alteration in different media, retaining a stable role throughout. No details exist regarding supernatural abilities, combat involvement, or physical appearance.