Margo, daughter of Fula City's mayor Oliver, has fair skin, short magenta hair, and purple eyes. She wears a pink dress jumper over a white cape-like shirt featuring rose pink lining, gold buttons, and a yellow bow, paired with white socks held by pink strings and pink shoes.

Following a rescue from a mountain forest rockslide near Fula City by the Mythical Pokémon Zeraora, Margo forms a secret bond with it. She aids its recovery from injuries and brings regular offerings, including food and Moomoo Milk. This bond remains hidden due to a decades-long rumor—spread by previous mayors, including her father—claiming Zeraora perished in a forest fire fifty years prior, a lie intended to shield it from aggressive human seekers which fostered mutual distrust.

Fearing Zeraora's discovery during Fula City’s annual Wind Festival might reignite human hostility, Margo sabotages the event to protect it. She obstructs train tracks with rocks, fills fountains with soap, and steals the sacred Eternal Flame beacon (used to summon the Legendary Lugia), hoping its absence would cancel the festival and deter trainers from the forest.

When poachers target Zeraora, Margo intervenes directly, leading to her needing rescue by Ash Ketchum. Later, during a combined fire and toxic spore outbreak endangering the city, Margo prioritizes collective safety over secrecy. She collaborates with Ash and Zeraora to combat the flames. During this crisis, her father publicly revokes the lie about Zeraora’s demise, affirming a new coexistence and allowing Margo to openly acknowledge her friendship.

Personality-wise, Margo displays warmth and protectiveness toward Pokémon, especially Zeraora, though these instincts sometimes manifest as deception or drastic measures like festival sabotage. She demonstrates honesty in critical situations, confessing her role in the disruptions during the city's disaster. She is occasionally seen with wild Pokémon like Ditto and Teddiursa, though no evidence confirms she formally caught them.