Ran Mōri, daughter of private detective Kogoro Mōri and lawyer Eri Kisaki, experienced her parents' separation at age seven and continues striving to reunite them. She shares a deep bond with childhood friend Shinichi Kudō, their relationship evolving significantly during a New York trip where they encountered Vermouth of the Black Organization; Ran saved Vermouth from a fatal fall, earning the moniker "Angel". Following Shinichi's disappearance, she cares for Conan Edogawa (Shinichi in a child form), introduced as a distant relative, treating him like a younger brother while periodically questioning his true identity.

A student at Teitan High School, Ran captains the karate club and holds a Kanto regional championship title, showcasing exceptional martial arts skill with a karate black belt and judo proficiency. Her physical capabilities include remarkable strength, agility, and reflexes, demonstrated by prying open elevator doors and dodging bullets. She excels in household management, cooking, and sewing, and displays uncanny luck in games of chance. Despite her combat expertise, she harbors an intense fear of the supernatural and horror.

Ran exhibits profound empathy, patience, and a strong sense of justice, though she reacts impulsively and physically when defending loved ones. Her unwavering feelings for Shinichi often make her oblivious to others' romantic interest. She independently manages her household, handling finances and domestic duties due to her father's unreliability, while also assisting his detective work by greeting clients and providing refreshments.

In "Detective Conan Magic File 2", Ran aids Shinichi's investigation into an alibi for a grandmother's murder. She recalls seeing a woman walking her dog daily in Beika Park, though this lead initially stalls. A disagreement with Shinichi over unsolvable mysteries leads to a week-long argument, resolved when they hear Reiko Akiba perform "Amazing Grace", a moment inadvertently foreshadowing a future case.