Ellie Yokosuka, operating under the alias Hairpin Green, is a member of the young hacker collective Main Trunk, utilizing her skills for beneficial purposes. Initially presented as a quiet, reserved high school student active in her school's computer club, she evolves into a vital asset within the hacker team. Her exceptional technical abilities and profound loyalty to fellow members drive her contributions, marked by resourcefulness and unwavering dedication to the group's objectives.

She later emerges as one of five individuals capable of transforming to defend Okuyama International Circuit against mysterious creatures seeking an unknown energy source beneath it. Fighting under the codename Hairpin Green alongside her fellow transformed defenders, her commitment transcends her technical role, showcasing steadfast determination to apply her abilities for broader protection despite adversity.

Her personality reflects ENFJ traits—extraversion, intuition, feeling, and perceiving—manifesting in her ability to connect with others, creative problem-solving, and spontaneous adaptability. Idealism and empathy fuel her motivations, inspiring her to encourage others and forge unique paths, maintaining a self-focused outlook centered on personal fulfillment. Analysis also suggests an Enneagram Type 3w4 ("The Achiever"), highlighting ambition, competitiveness, and a strong work ethic aimed at recognition and success, alongside potential struggles with identity and self-worth beneath her resilient exterior.

Her background emphasizes unwavering dedication to supporting allies, consistently prioritizing their well-being through empathetic action. This core loyalty defines her interactions within both the hacker group and the transformation team. She balances her reserved nature with intense focus during missions, channeling technical expertise into practical solutions during confrontations. Multicolored hair serves as a distinguishing physical trait.