The first events we know about in Duo's life occurred in AC 187, when he was already seven years old. He appeared on the V08744 at L2, which was very poor due to the fact that most of the its residents were impoverished immigrants from all over the Earth. There was a great deal of fighting in the colony, which left behind a lot of abandoned buildings, as well as orphans. Duo was not born on the colony; rather, he drifted there, probably by stowing away on a shuttle. At that time, he didn't have a name. He was taken in by a kid named Solo, who led a group of orphans. Solo was infected with a virus that was burning its way through the entire colony. A vaccine had been discovered, but the authorities saw no reason to distribute it to the poor or homeless. Duo snuck into a hospital and stole enough vaccine for everyone but himself...but it was too late for Solo. Before he died, Solo said to Duo "You're a nice guy...I wish I could stay with longer." Duo replied, "Don't be stupid...you shouldn't give up." Later, Solo said "Even after I die, I'll always be with you...so be nice." When Solo died, Duo said, "Fine...if Solo's with me, we'll be Duo." When Duo realized that he didn't have any vaccine for himself, he decided that he didn't mind if he died. He didn't even get sick, though. He decided to stay on as leader of the group in Solo's place.

One day, perhaps out of anger at the Federation, he took the orphans to a Federation base to steal food. They were caught and managed to escape, but the people of the colony tore down the abandoned building they had been living in. Maxwell Church took all the orphans in. They fed them and gave them clothes and one of the nuns, Sister Helen, tried to cut Duo's long hair, but Duo refused to let her. So instead, she braided his hair, just for the sake of neatness, and Duo really liked it. The orphans that Duo had been with were adopted out, but Duo never managed to find a permanent family; he always got kicked out of the house in a day because he was such a trouble maker. One day, Duo got into a very bad fight with a group of five kids; he ended up putting them all in the hospital. Because of this, he was threatened with expulsion from school. When Sister Helen asked Duo why he had gotten into a fight like that, he said it was because the kids had called him names and told him he smelled like a sewer. Sister Helen hugged Duo and told him that he didn't smell, and that they would collect some snow for water so that they could wash. They got snow from off the roof of the church. Father Maxwell came back to find them; he'd just finished apologizing at the school for Duo. Duo felt really bad, but Father Maxwell said "It's alright. If they only want me to apologize for you, I'm happy to do so. Just go back to school tomorrow and work hard."

The next year, there was another uprising, turning the colony into a battlefield once more. Maxwell church became a makeshift hospital for the wounded for the resistance fighters that had made it their base. One of the resistance leaders decided that they needed an MS. When Father Maxwell objected, bringing up Heero Yuy , they struck him with the butt of a rifle. Duo told them that he would steal an MS for them if they would just leave the church, since the church was a place of sanctuary. The didn't believe him, but Duo ran to the Federation base. He had to run through gunfire, but he managed to make it to a truck that had a Leo in it, and he drove it back to the church. When he arrived, the church had been destroyed. He found Sister Helen barely alive in the ruins. Duo tried to leave so he could get a doctor, but Sister Helen kept talking. She said "The Federation forces attacked us, but we couldn't leave this place." Duo replied, "It's my fault. I stole the Mobile Suit." Sister Helen was now dying; she was having a hard time focusing. "The Father urged peace until the end." She touched Duo's cheek very gently and said, "May God protect you..." before her hand fell away. Duo cried and screamed like a lost soul, because he would never hear her sing again, or feel her warmth. It was the first time he had ever cried because of death. After the Maxwell church tragedy, Duo disappeared for a few years, finally ending up as a stowaway on Professor G's ship. Professor G let him stay, and eventually gave him Deathscythe to pilot.