Megumi Ayase reigned as Parthenon Productions' top idol star before Creamy Mami's debut. Mami's rapid ascent immediately challenged Megumi's established position, prompting her to declare a professional rivalry against the newcomer. This rivalry was fueled by jealousy over the public's shifting adoration and the romantic attention company president Shingo Tachibana directed toward Mami. Megumi harbored strong, unreciprocated feelings for Tachibana, intensifying her resentment.

Her personality blended arrogance and a spoiled demeanor with underlying determination and personal standards. The perceived threat to her career and romantic aspirations occasionally led her to attempt undermining Mami through less honorable methods. Megumi possessed long brown hair and blue eyes, typically dressed in distinctive stage attire featuring a dark pink dress with white frills, often accentuated by red lipstick and violet eye shadow.

Character development unfolded across the series and subsequent media. While insecurity and jealousy initially drove her actions, later narratives, particularly the OVAs, depicted a shift toward professionalism and reconciliation. The 1985 OVA featured a 16-year-old, non-magical Yu Morisawa collaborating with Megumi on a film project; Yu wore a wig to resemble her former Mami persona, signaling their move past animosity into a working relationship.

The 2018 spin-off manga "Magical Angel Creamy Mami and the Spoiled Princess" significantly expanded her character. It retold events through Megumi's perspective, delving deeper into her motivations, emotional struggles, and experiences navigating the intense competition and personal disappointments of the idol industry. This provided context for her original series actions, framing her jealousy and rivalry as responses to upheaval in her career and personal aspirations.