Laius Orteus is the son of King Jilq and Queen Gizelotte of the Orteus Kingdom and the older half-brother of Marianne. He is also the biological younger brother of Haruto Zenfis, though he remains unaware of this connection for much of the story. As the next in line for the throne, Laius initially presents himself with arrogance, pride, and a condescending attitude toward others. He is known for his rudeness and overbearing demeanor, which stem from his royal upbringing and the pressure to live up to expectations. Despite this, he is deeply fearful of his mother and follows her orders out of terror, revealing a more vulnerable side. He does care for his half-sister Marianne and shows protectiveness toward her.

Laius first encounters Haruto in a competitive context and suffers a decisive defeat. This loss becomes a turning point for him. Rather than harboring resentment, he develops a profound respect for Haruto's abilities and begins to see him as a rival and an insurmountable figure. Motivated by this loss, Laius embarks on intense training, focusing on improving his combat skills and physical strength. He is a skilled warrior, though his exact magical abilities are not highlighted compared to his physical prowess. His dedication to self-improvement reflects his underlying drive to prove his worth beyond his royal status.

In the story, Laius functions as a supporting character who transitions from an antagonist figure to an ally and admirer of Haruto. His development is marked by a shift from arrogance to humility and respect, as he learns to acknowledge strength in others. By the time he enters the academy, he looks up to Haruto and treats him as a benchmark for his own growth. His key relationships include Haruto, whom he sees as a rival and role model; his mother, whom he fears; and his half-sister Marianne, whom he cares for. Laius's notable abilities lie in his combat skills and his unwavering determination to overcome his limitations through rigorous training.