Khun Aguero Agnes originates from the Tower's Ten Great Families as a son of Khun Eduan. His direct lineage remained uncertain due to his mother's lower status. Raised with his older sister and cousin Kiseia, he endured intense maternal pressure to make his sister a Princess of Zahard. At age ten, he survived the Khun Family's lethal "official fights," where child combatants battled to the death; his victory granted him the family crest while defeated peers faced abandonment. He later betrayed his sister by aiding her rival Maria to become a Princess, drawn to Maria's kindness amid the Khun Family's manipulation. This act triggered his sister's suicide and the Agnis branch's expulsion from the family—a fate deemed worse than death—leaving him isolated and instilling a deep fear of abandonment. Kiseia developed lasting hatred toward him for this betrayal. Before entering the Tower as a Regular, he plundered Khun Eduan's treasure room, obtaining powerful artifacts like the cloning bag Manbarondenna, a high-grade suspendium pulley, and an Armor Inventory. On the Tower's Second Floor, he formed a pivotal alliance with Twenty-Fifth Baam and Rak Wraithraiser. His strategic brilliance surfaced immediately when he prioritized alliances over combat in their first test, rejecting subjugation and emphasizing a ruler's mindset. As a Light Bearer, he manipulated outcomes using tools like Manbarondenna for complex deceptions, such as cloning the crown during the Crown Game. His lighthouse mastery and tactical innovations—including storing allies in his inventory—repeatedly altered tests. Despite his calculated exterior, he protected Baam by thwarting Ho's assassination attempt. Baam's apparent death during the Submerged Fish Test deeply impacted him. He deduced Rachel's involvement, feigned loyalty to her, and secretly plotted her downfall. Leading a climbing team, he instructed them to outwardly protect Rachel while inwardly despising her, labeling her "the woman who killed my most precious friend." His goal shifted to leading the Khun Family to avenge Baam. Learning of Baam's survival via the AI Emile, he prioritized reuniting with him and crucially aided Baam's escape from FUG during the Workshop Battle. His development included acquiring the Yeon Family's healing flame and an ice spear from Evan Edrok, expanding his combat versatility beyond Light Bearer duties. His strategies evolved to support Baam's objectives, such as infiltrating the Nest to rescue Ha Jinsung. Though habitually distrustful, his bond with Baam drove him to shield Baam from exploitation while acknowledging Baam might outgrow their alliance. Physically, he possesses pale skin, cyan eyes, and distinctive sky-blue hair, often partially covered by a blue bandana. His attire typically includes refined, practical clothing like white shirts and grey jeans. Despite his youthful appearance, his age likely spans centuries due to the Tower's time dilation, particularly given the Princess selection timeline involving Maria. He maintains a tranquil yet manipulative demeanor, exploiting others unhesitatingly to achieve goals. His premature adulthood forced by Khun Family politics fostered an ironic longing for childhood, manifesting in occasional petty or playful behavior. Despite emotional guardedness, he exhibits profound loyalty to those he values, especially Baam, for whom he willingly endures extreme risks.