Ageha Yamaguchi is a character from the anime Sacred Seven. She is a high school student who appears to be around sixteen years old, with pink hair and blue eyes. Beyond her student life, Ageha is a skilled mechanic and also a talented pilot. She is a member of the in-universe musical group Nightfly O'Notes.

In terms of personality, Ageha is initially presented as reserved and calm, rarely displaying her emotions openly. She possesses a strong desire for independence and self-reliance, driven by a deep-seated fear of becoming a burden to others. This can make it difficult for her to accept help, even when it is offered willingly. Despite her composed exterior, she is a deeply caring person who is willing to go to great lengths to protect those she cares about. She acts quickly when she sees someone in danger and dedicates herself to the safety of her friends and loved ones.

Ageha's primary motivation is to prove her own worth and to protect others, often by combining her technical and piloting skills. Her role in the story is as a key supporting character. Her abilities as a mechanic and pilot are crucial to the team's operations. She shares a significant and complex relationship with the protagonist, Alma Tandouji. Initially suspicious of him due to her firsthand experience with the destructive potential of the Sacred Seven powers, she eventually develops a tentative mutual respect with Alma, which grows into a close friendship as their paths continue to cross. This relationship marks a key part of her development, as she moves from suspicion to trust and cooperation.

Regarding her notable abilities, Ageha is not a direct combatant like the series' main power-wielders. Her primary strengths lie in her mechanical expertise and her proficiency as a pilot, making her an invaluable asset in support and tactical roles.