Liona Printzesa, most commonly known as Leona, is a main character from Dragon Quest: Dai no Daibōken. She is the princess of Papnica, a kingdom renowned for producing powerful mages, and is herself training to become a sage. She first appears when she travels to Dermline Island to undergo the ritual necessary to become a full-fledged sage, where she meets the protagonist Dai. Their initial encounter is marked by mutual dislike, as Leona bluntly comments on Dai's small stature and unimpressive appearance, and Dai finds her outspoken manner off-putting. However, during her stay on the island, she gives Dai a ceremonial knife called the Sun Knife and encourages him to stop dwelling on his inability to use magic and instead focus on refining his swordsmanship. This moment marks a turning point in their relationship, and Leona becomes Dai's first human friend.

Leona is characterized by a strong-willed, spirited, and remarkably candid personality. She does not hesitate to speak her mind, even to those of higher status or authority, and she is known for her boldness and courage. Despite her youth, at fourteen years old, she possesses a sharp intellect and a natural aptitude for leadership. After the Undead Knight Hyunckel destroys Papnica and her father the king goes missing, presumed dead, she becomes the de facto leader of her kingdom. In this role, she demonstrates considerable diplomatic skill and charisma, organizing a summit of world leaders to coordinate resistance against the Demon King's forces. She is also deeply compassionate and fair-minded. When Hyunckel, the general who orchestrated her country's ruin, later submits himself to her judgment, she chooses not to punish him with death. Instead, she sentences him to spend the rest of his life fighting as a true disciple of Avan, atoning for his past by protecting the innocent. This decision earns the respect of even the cynical mage Matoriv, who remarks that with her in charge, Papnica may recover.

Leona's motivations are rooted in a strong sense of justice and a desire to protect her people and the wider world. She deeply admires Queen Flora of Carl, a legendary figure who once fought alongside the hero Avan, and aspires to emulate her strength and wisdom. As the story progresses, her personal goal shifts from merely surviving and rebuilding her kingdom to actively contributing to the fight against the demonic threat. She is driven to be more than a damsel in need of rescue; she insists on being a part of the battle in her own way.

Her role in the story evolves significantly. In the early arcs, she is a motivating presence for Dai and a target for the enemy to exploit, most notably when the ice-and-fire general Flazzard takes her hostage. After being rescued, she participates in the adventure for a time, serving as the party's primary healer while the martial artist Maam is away training. She later leaves the group to forge political alliances and coordinate the human resistance. In the final confrontation with the Demon King Vearn, she is formally inducted as the fifth Disciple of Avan, inheriting the Crest of Avan from Queen Flora. This allows her to learn the great barrier spell Minakatol, which becomes crucial for the party to breach Vearn's palace. In the final battle, she acts as Dai's emotional anchor, encouraging him when he falters and even striking Vearn with a knife to bolster Dai's resolve. She is the only one among the main party to land a wound on Vearn's true form.

Key relationships define her character. Her bond with Dai is the most significant, hinted to be romantic on both sides, though it never becomes explicit. She is one of the few people who can reach through to Dai emotionally, and his desire to protect her often triggers his most powerful abilities. Her relationship with Hyunckel is complex, moving from that of a victim and her nation's destroyer to a leader and a redeemed ally. She also shares a close mentor-student dynamic with Queen Flora, who ultimately passes the mantle of Disciple to her. Among the other Disciples, Leona interacts most directly with Maam and Popp, with Popp often being the target of her sharp tongue.

In terms of character development, Leona grows from a somewhat brash and untested princess into a composed and decisive leader. She learns to balance her impulsive nature with the weight of responsibility. Her greatest growth occurs when she chooses to leave the safety of her restored kingdom to fight alongside her friends, and again when she masters Minakatol, transforming from a supporter into a linchpin of the strategy against Vearn. She also matures emotionally, learning to channel her outspokenness into diplomacy and her stubbornness into unwavering resolve.

Notable abilities stem from her training as a sage. She is proficient in a range of spells, though her direct combat magic is limited to intermediate spells such as Mera, Merami, Hyado, Hyadarko, and Gira. Her most valuable skill is her mastery of healing magic, particularly Behoma, which she uses repeatedly to save her allies in battle, notably during the fight against Baran. She is also capable of casting ZaoLal, a resurrection spell, though it is not always successful. Later in the series, she learns the advanced barrier magic Minakatol, which requires multiple casters and becomes essential for the final assault on Vearn's palace. She also wields the Gold Feather and Silver Feather, items gifted by Avan that enhance her support capabilities. Leona is not a frontline combatant; her physical strength and stamina are average for a human her age, and she rarely uses weapons, though she demonstrates bravery by facing Vearn directly with a knife. Her true contribution to the party is her intelligence, leadership, and healing power, making her an indispensable part of the group effort against the Demon King.