Pop Harukaze, younger sister of Doremi Harukaze, initially exhibited a condescending and spiteful attitude toward her sibling, mocking Doremi's clumsiness. This behavior originated from underlying envy and feelings of inferiority, particularly regarding Doremi's friendships and their mother teaching Doremi piano while excluding Pop. Despite this, adults and peers consistently praised Pop for her responsible, mature demeanor, often perceiving her as charismatic, respectful, and kind—especially when defending friends or confronting mean behavior.

Physically resembling Doremi, Pop has light skin and round mulberry eyes with a red hue. Her pink hair forms wing-like pigtails with loose tufts at the bottom. Her attire evolved: she first wore a light pink and white kindergarten smock with a red skirt and light pink shoes, later switching to a light cyan and white blouse while retaining the skirt and socks.

Discovering Doremi's witch apprenticeship led Pop to become the fourth witch apprentice. After purchasing Majorika from the magic shop and witnessing the others' transformations, she joined to protect their secret. As an apprentice, Pop demonstrated greater initial competence than Doremi, progressing faster in training. However, age constraints like early bedtimes limited her advancement, preventing attendance at nocturnal exams. She never obtained her crystal ball until the series' penultimate episode. Her fairy companion is Fafa, and her crystal ball features a red clover. Her spells include the transformation chant "Pretty Witch Pop-cchi!" and the incantation "Pipitto Puritto Puritan Peperuto!"

Pop retained the original Tap device for transformations and used a Kururu-type Pollon wand requiring Magic Spheres, unlike the upgraded wands of other apprentices. Her transformation sequence involves playing a unique melody on the Tap, changing into her witch uniform. She could summon a magic broom for flight.

Relationships shaped Pop's growth: early friction with Doremi evolved into mutual respect and closeness after addressing envy and misunderstandings. Hazuki Fujiwara viewed Pop as mature and adorable, while Aiko Senoo teased Doremi about Pop's comparative responsibility; Pop admired Aiko and thanked her for befriending Doremi. She shared a strong bond with Onpu Segawa, even sacrificing her magic to help Onpu recover from a coma. Interactions with Momoko Asuka were minimal but positive, focused on cooking tips. Pop and Hana-chan developed a close yet occasionally fraught relationship due to mutual envy over each other's circumstances, though they collaborated in caretaking.

In the light novel sequel, Pop appears as a sixth grader at Misora Elementary School under Seki's instruction, aiming to enroll in Karen Girls Academy for a piano career. Her appearance is slightly older and thinner than in the anime, with smaller hair wings. She maintains her teasing dynamic with Doremi but exhibits greater academic seriousness.

Trivia notes include her 200-yen allowance, her name's etymology ("spring breeze" + "pop" sound), and her reversed color scheme compared to Doremi (pink hair with red theme versus Doremi's red hair with pink theme). A production error occasionally depicted her pupils as black instead of purple. She plays the trumpet despite piano ambitions and remains the only character using a brass instrument.