Leopard, also known by her codename Doronjo, is a nine-year-old girl and the main protagonist of Yatterman Night. She is a direct descendant of the original Doronjo, the leader of the Doronbo Gang from the classic Yatterman series. Leopard lives with her mother, Dorothy, and two close family friends, Voltkatze and Elephantus, in a poor region outside the wealthy Yatter Kingdom. She grows up unaware of her heritage until she discovers that Dorothy, Voltkatze, and Elephantus are descendants of the legendary villains. Her mother encourages her to be a good person and avoid the path of villainy. However, when Dorothy falls gravely ill on Leopard's ninth birthday, the Yattermen refuse to provide the medicine needed to save her, resulting in Dorothy's death. This act of cruelty shatters Leopard's belief in the Yattermen as heroes and drives her to take on the mantle of Doronjo, reforming the Doronbo Gang alongside Voltkatze and Elephantus.

Leopard is a strong-willed and determined young girl who refuses to give up hope even in the face of overwhelming adversity. She is characterized by her optimism and her ability to stand back up after every trial, but she also struggles with the weight of her ancestors' legacy and the harsh realities of her world. Her initial motivation is revenge against the Yatter Kingdom for the loss of her mother, but as she encounters more suffering caused by the corrupt Yattermen, her goals expand to fighting for justice and freeing those oppressed by the regime. Throughout the series, she pilots various mecha, such as the Forehead Flicking Mecha and the Genghiskhan mech, in battles against Yatter soldiers and generals. Her leadership, courage, and empathy for others are central to her role as the leader of the new Doronbo Gang.

Key relationships include her bond with Voltkatze and Elephantus, who serve as her loyal partners and caretakers. She also forms connections with the children Alouette and Galina, whom the gang meets on their journey, and these relationships help deepen her resolve and sense of responsibility. Leopard undergoes significant development from an innocent, hopeful child into a determined freedom fighter who embraces her identity as Doronjo, not as a villain but as a symbol of rebellion against tyranny. Her notable abilities lie not in physical strength but in her indomitable spirit, her tactical thinking in mecha combat, and her ability to inspire loyalty in those around her.