The pilot Herro Yuy is one one of the most glommy and serious Gundam Pilots. His real name is still unknown but his code name was named after the martyred leader of the space colonies. Herro was raised by a scientist named Dr. J. Herro was trained at a very young age as a killing machine, a mobile suit pilot, demolition, combat, fencing, and computer hacking. Herro's insperation for continuing the war is the pain the people in the space colonies feel. He feels obliged to protect them and end the war. Although Herro is a semi almost perfect soilder, he can't deprive all his emotions away from himself. He neglects his allys, acts cold blooded against his enemys, and suicidal to his own life sometimes. After the daughter of the prime minister (Relena) discovers Herro's true identity, Herro's all no emotion factor declines slowly as his feeling tawords Relina grows. Sometimes, Herro hesitates to kill Relena but always back away.

Herro encounters Duo Maxwell after when Duo bust Herro out of a OZ hospital and saves him. Although Herro still shows no gratitude to Duo, he toyed with him on one of the missions. Herro then meets Trowa later on.