AE3803, also known as Red Blood Cell, is a main character in the anime series 'Hataraku Saibou' (Cells at Work!). She is depicted as a diligent and somewhat clumsy red blood cell responsible for delivering oxygen and carbon dioxide throughout the human body. Her persistent nature often leads her into various unexpected situations, highlighting the challenges faced by red blood cells. Despite her frequent mishaps, she remains optimistic and dedicated to her duties, embodying the essential role red blood cells play in maintaining the body's overall health and function.