Miguel is the son of professional Megaloboxer Mac Rosario and Maya. He drives Mac's boxing career and personal choices. After a near-fatal injury leaves Mac facing paralysis, Maya consents to an experimental cybernetic implant, hoping to ensure Miguel keeps his father despite the risks.

Miguel embodies the future Mac fights to protect through boxing, enabling him to provide for his family. However, the implant causes violent dissociative episodes called "Mac Time," threatening Mac's well-being and family stability. Miguel underscores the theme of preserving what remains after loss.

The narrative links Miguel thematically to recurring hummingbird imagery. A hummingbird poem, used as a bedtime story, metaphorically represents guidance, hope, and finding purpose. The hummingbird signifies what characters like Mac, through protecting Miguel, strive to safeguard – "what they have left." While Miguel lacks extensive independent development, he fundamentally shapes Mac's story, framing it through familial duty, sacrifice, and the consequences of cybernetics.