DB5963

DB5963 (credited as Transfused Red Blood Cell 1 (輸血赤血球１) in the anime) is a red blood cell that is transfused into the host body of the main series after experiencing massive blood loss. He acts as a leader to the rest of the transfused red blood cells in delivering the oxygen to the rest of the body.

Later on, U-1146 shows him and AE3803 around the small intestine before leaving to get them some tea. He later forgets about them as there is a Campylobacter invasion in the small intestine.