Destiny Heartwarming is a central figure in the original movie A Tale of Perishing, which serves as the fictional setting for the story. She is portrayed as a kind-hearted and gentle young woman who serves as the heroine of that tragic film. Within the narrative, she is the sheltered daughter of the mayor of the Last Town, having been raised without full knowledge of the world's true dangers. Destiny is characterized by her pure intentions and a deep-seated desire to help others, a trait that is both her greatest strength and a source of unintended complications, as her well-meaning actions can sometimes create unexpected trouble.

Her primary personal motivation is the dream of building an orphanage to provide a safe haven for children in need. This dream is a defining aspect of her character and drives many of her major decisions throughout the story. In the original, unaltered plot of A Tale of Perishing, Destiny’s role is a tragic one: she falls in love with the hero, Luke Braveheart, but is ultimately killed by the monstrous Voids, an event that causes Luke to succumb to despair and darkness. However, the narrative introduces significant changes to her fate. Inspired by a character created by the anime director Natsuko Hirose, Destiny develops a new passion for cosplay, specifically adopting the persona of Serval Cat Mask, and trains her body intensively, becoming notably strong and muscular. With this newfound strength, she takes the initiative to open her own orphanage, which she names the Serval Cat House, to care for children, particularly those from the impoverished Despair District.

Destiny's key relationships evolve significantly. Her bond with Luke Braveheart is central, though its tragic conclusion in the original story is a major plot catalyst. Her relationship with Natsuko Hirose is complex, beginning with Natsuko viewing her as an unintentional troublemaker but growing into a close friendship, with Destiny even asking for Natsuko's help in saving the children. She also develops a strong partnership with the character Justice, whom she affectionately calls "Jas-chan," as he helps her run the orphanage. Throughout the series, Destiny faces difficult choices to support her dream, including entering into an agreement with a wealthy Chairman to secure funding for her orphanage, only to later break that engagement to pursue her own path. She later agrees to it again when the Voids’ attacks make running the orphanage difficult. Her personal development transforms her from a sheltered, tragic maiden into a determined, physically powerful young woman who actively fights for her beliefs and the safety of the children under her care. Her notable abilities, beyond her unwavering kindness, include the significant physical strength she acquires from her cosplay-inspired training, allowing her to perform feats such as carrying two children on her shoulders with ease.