This Doctor is the medical professional who treats Shun Yashima during a severe, life-threatening allergic reaction (anaphylaxis) triggered by accidental egg consumption while Shun's parents are absent. The Doctor administers critical emergency intervention to manage the acute symptoms. Subsequently, the Doctor oversees Shun's enrollment in a clinical study designed to build egg allergen immunity through controlled exposure therapy (immunotherapy), facilitating Shun's long-term condition management.