Sindbook functions as a primary animal companion to the protagonist, hailing from Fenarinarsa alongside two other creatures resembling a monkey and a bird. In the original series, this canine manifests as a brown dog sporting a mop-top hairstyle and a bushy, mustache-like muzzle. He occasionally reveals hidden talents, such as crafting intricate snow sculptures during specific episodic events. Within his trio dynamic, Sindbook embodies the superego role—exhibiting stoic, responsible traits that counterbalance the emotionally expressive bird and the balanced monkey. His personality intermittently delivers snarky commentary for comic relief, yet maintains unwavering loyalty to his charge.

When the narrative transitions to the sequel series set in an alternate dream realm, Sindbook’s counterpart emerges as a blue dog named Cookbook, distinguished by a white muzzle and an oversized red nose. This iteration adopts an older, lethargic demeanor paired with self-assured worldliness. The two canines directly interact when their respective magical companions cross paths in the sequel’s storyline. Across international adaptations, Sindbook undergoes name alterations like "Bonkers" in select English dubs, while the Italian version retains "Cookbook" for the sequel counterpart. The character appears consistently throughout the original television series, its related OVAs including the crossover "Long Goodbye: Mahō no Tenshi Creamy Mami VS Mahō no Princess Minky Momo", and subsequent sequel media.