Lisa Alpacas is the princess of the Ogre Kingdom, also known as Oglustan. An ogre of royal standing, she grew up as the strongest ogre in her homeland. Dissatisfied by the lack of partners matching her strength within the kingdom, she departed Oglustan seeking a worthy mate.

Her appearance features pink skin, long white hair extending past her hips, red eyes, and distinct red markings on her cheeks and shoulders. She possesses two horns on her head and a tail. Her typical attire consists of a backless jeweled black top fastened to a grey choker, a pink loincloth with a matching skirt secured by a metallic belt, brown gloves, brown boots, and a brown cloak draped around her waist.

Personality-wise, Lisa demonstrates a strong belief in ogre superiority. She initially pursues Peter Grill solely to obtain his genetic material for powerful offspring, openly stating her intention to leave after conception. Yet her actions reveal cunning and strategic manipulation: she studies Peter's behavior, exploits his weaknesses, and employs blackmail—such as threatening to reveal their encounters to his fiancée, Luvelia Sanctos—to control him. Despite this pragmatic exterior, she occasionally shows deeper investment, proposing Peter abandon his human life to rule as king of the ogres beside her.

Her primary role unfolds after Peter Grill wins the title "Strongest Man in the World" at the Grand Fighting Tournament. Witnessing his victory, she and her younger sister Mimi Alpacas pursue him. They corner Peter in his room, using physical persuasion to initiate sexual relations, subsequently leveraging the encounter to blackmail him into continued compliance.

Throughout conflicts, Lisa displays tactical ingenuity. She anticipates Peter's attempt to intentionally lose a duel to shed his "strongest man" status, countering by threatening to expose his infidelity. She also negotiates alliances and schedules with other women pursuing Peter, like the elf Vegan Eldriel and the orc Piglette Pancetta, to share access. Her rivalry with Vegan involves physical confrontations and mockery over physical attributes, though they cooperate temporarily for mutual benefit.

Her relationship with Mimi combines collaboration and occasional friction, typical of their sisterly dynamic. While both share the goal of obtaining Peter's offspring, they also compete for his attention. As the de facto leader of Peter's unwanted harem, Lisa coordinates the group's efforts while maintaining her own agenda. Her background as a warrior princess is reinforced by immense physical strength, demonstrated by defeating multiple ogre warriors single-handedly.