Amy Stapleton serves as the midfielder and battle tactician for Team Satomi in the Immortal Grand Prix. She is a fourteen-year-old child prodigy of Irish nationality. Her intellectual capabilities are extraordinary, as she completed college-level studies by the age of seven. This exceptional intelligence makes her the strategic core of her team, responsible for analyzing opponents and devolving race tactics under immense pressure. Physically, she is acknowledged as the weakest member of Team Satomi, a limitation that defines her combat and racing style. To compensate for this, she relies on blistering speed, agility, and surgical precision, embodying a fighting approach that favors rapid strikes and calculated dismantling of opponents rather than brute force.

Personality-wise, Amy presents a quiet and sympathetic demeanor that often leads her teammates to underestimate her. Off the track, she is gentle and soft-spoken, frequently acting as a mediator who patches up conflicts between the more hot-headed members of Team Satomi, particularly Takeshi and Liz. Despite this calm exterior, she possesses a ferocious tenacity during races, displaying a fierce competitive spirit that contrasts sharply with her usual reserved nature. Her character carries a deep sense of loneliness and a yearning for family, stemming from her childhood. Her parents were often absent due to work obligations, leaving her emotionally adrift. This unresolved grief is a central part of her character, highlighted in the episode "The Ghost," where her longing for her absent parents is brought to the forefront. This vulnerability adds emotional depth to her otherwise analytical and composed racing persona.

Amy’s most unique attribute is her bond with Luca, her cybernetically enhanced calico cat. Luca acts as her co-pilot and snarky confidant, and during races, Amy synchronizes with him to form a composite personality that amplifies their combined strategic and combat prowess. For much of the series, Amy is the only person who can hear Luca’s voice while they race together in her mech. This private communication underscores her initial isolation, as she relies on this unique partnership to function as the team’s tactician. Her role within the story is vital, as she not only provides the strategic backbone for Team Satomi but also serves as an emotional stabilizer. Her empathetic insight helps preserve unity among her teammates, chipping away at her own solitude as she gradually forms stronger bonds with them.

Amy undergoes significant development throughout the series, marked by a major setback and a powerful recovery. In the second season, she is injured during a collision in a race against Team White Snow. This injury forces her to be hospitalized and temporarily replaced in the midfielder position by Andrei Rublev, a retired legend who becomes the team’s coach. During her recovery, she demonstrates remarkable resilience. Despite being under strict medical oversight and having recently been hospitalized, she manages to defeat Andrei in a simulated battle, proving her determination to reclaim her place on the team. Her comeback race features an inspiring declaration where she admits her fear of getting hurt but affirms that her love for racing is stronger than that fear. This moment solidifies her arc from a solitary genius defined by her intellect to a cornerstone collaborator who has found belonging. By the series finale, competing in the 2051 season, her evolution is complete when the rest of Team Satomi gains the ability to hear Luca’s voice during races, symbolizing her full integration into the team and marking her transition from a lonely prodigy to an integral part of a family.