Younger Prince of Nohr and  voiced by Max Mittleman.

Leo is portrayed as a character who possesses a keen intellect, one that he devotes towards the study of magic and strategy. In this regard, he is known to be diligent and hardworking in honing his expertise to a fine, sharp edge, to the point where he is widely regarded as a genius who is more than capable of flawlessly handling any difficult situation. Further complementing this facet of Leo's personality is the cold demeanour of calm that he assumes, one that he resolutely maintains even in the face of trying situations.

Beneath this exterior of perfection that Leo exudes, however, is a deep-seated inferiority complex that is specifically directed towards the Avatar. This inferiority complex is not one that takes its roots from the Avatar being his intellectual superior, stemming instead from the fact that they receive far more attention from Xander and Camilla than he does. This dimension of Leo's character is unveiled through his supports with the Avatar, where he, while in the midst of tutoring them in the art of strategy, reveals his jealousy of the Avatar having received far more attention than he has from both Xander and Camilla.

Like his half-sisters Camilla and Elise, Leo hates his own mother as she never loved him and even using him as a tool in order to gain his father's favor during the Concubine Wars. In his A-support with his half-sister Elise, he stated that his mother never loved him and considered him as her instrument and lever. In return, he held nothing but hatred & contempt toward her.

Leo has shown that he truly cares for his elder step-sister, Azura as much as Xander and Camilla do. In his supports with Azura, Leo admires Azura's song. He apologizes to Azura, stating that her singing entranced him, as he had never heard music like that before. Leo is also aware of the stories about the Nohrians' mistreatment towards both her and her mother, Queen Arete.

In spite of him being recognised as an intellectual genius, Leo is not blinded by his reputation to the point of arrogance and pomposity. He is instead known to treat the people whom he engages with the utmost respect and civility, a fact that helps him to cultivate strong relationships with relative ease. His supports with Mozu prove this point, where he, in response to her woefully commenting that she is not the right person to turn to for strategy advice, kindly informs her that different people possess different strengths and outlooks that help make them who they are.

Leo has also been portrayed to be quite the romantic, capable of capturing the heart of the lady whom he has fallen in love with. This fact can be observed throughout his S-Supports, where he is shown to refrain from being too forceful in his attempt to convince the person he loves to accept him, choosing instead to adopt a slow, yet steady approach to prove the sincerity of his heart. Leo's S-Support with Nyx stands as a good example to prove this fact; in this support, he gently melts away the chronic insecurities that she harbors of being trapped in the body of a child by urging her to envision herself as an adult before carefully getting her to imagine him as her spouse. In doing so, he succeeds in convincing Nyx of the sincerity of his love, following up his feelings with a proposal.

Leo hates his father's retainers Iago, Hans and Zola just as his half-siblings do. In Birthright and Conquest, Leo personally executes Iago for attempting to kill the Avatar many times and for attempting to save his skin by begging for mercy. In Revelation, when Zola attempted to escape by taking princess Sakura as a hostage, Leo immediately executed Zola for his cowardly actions of taking a princess hostage.

Leo is known to be ruthless in his treatment of those whom he has developed a tremendous disdain for. This is supported in both the Birthright and Conquest routes with Iago, where he is sick of Iago's pitiful attempts for mercy and promptly executes him.

Leo is said to like tomatoes the most out of everyone in the army. His birthday is June 30.