Marmo operates as a core antagonist within the Selfish Kingdom's forces, serving King Jikochuu alongside colleagues Ira and Bel. Her appearance features long aqua or mint-green hair, yellow eyes, pale skin, and distinctive bat-wing structures behind her ears. She wears an asymmetrical violet and pale white jacket-like dress adorned with red trellis patterns, a violet Cossack hat, a greyish-purple bracelet, and thigh-high red boots.

Personality-wise, Marmo embodies greed and vanity, prioritizing self-interest and personal beauty above all. She exhibits laziness, avoids strenuous activity, and reacts with extreme distress to perceived imperfections like pimples or potential sunburns. She frequently mocks Ira, belittling him as childish while acknowledging his affection for Cure Diamond. Despite their conflicts, she shares mutual resentment toward their demanding superior, Bel, with Ira.

Marmo's abilities include transforming human selfishness into Jikochuu monsters and generating purple energy whips for combat. In one significant arc, she inadvertently acquires a counterfeit Lovely Commune device, enabling a temporary heroic alter ego named Cutie Madame (or Glitzy Marmalade). This form adds red glasses, a fan weapon, wind-based attacks, and finger-launched flame beams. Her tenure as Cutie Madame involves misguided attempts at heroism, such as disrupting a children's play, before defeat reverts her.

Her narrative involvement spans the primary conflict against the Pretty Cure team. Key developments include receiving enhanced power via Blood Rings from Bel, though she later relinquishes these when Bel undergoes his own transformation. Following the defeats of King Jikochuu and Proto Jikochuu, Marmo retreats alongside Ira and Bel, departing into obscurity.

Etymologically, her name derives from Mammon, a demon representing greed within the seven deadly sins. She remains the sole known female operative within the Selfish Kingdom's ranks.