Duo was born on the colonies in the year After Colony 180. Duo was abandoned young as a child, and has no recolection of his real name or his real family. By the year After Colony 187, Duo had joined a street gang, led by a boy calling himself Solo. Solo fell ill with a fever in AC 187, and declared Duo his successor, telling Duo that he would always be with him. Duo then took on the name "Duo," saying "If Solo's with me, we'll be Duo."
Duo and the rest of his gang were taken in by a foster care calling themselves the Maxwell Church. Duo watched as all of his friends got adopted, and he was also eventually adopted. He was sent back by his adoptive parents though, and Father Maxwell and Sister Helen, the leaders of the Maxwell Church, adopted him. He was then given his signature braid, and made his firm stance that he believed only in the God of Death, as he only saw deadpeople, and never saw any miracles.
The colony that Duo lived on was eventually taken over by rebels, and Duo made a deal with the rebels. If he could steal a Mobile Suit for them, then they would leave the church alone. Duo succeeded in stealing a a mobile suit, but all that he returned to what would later be called the "Maxwell Church Tragedy." He discovered in the midst of 245 dead people a dead Father Maxwell, and a dying Sister Helen. Sister Helen died in Duo's arms, and Duo took on the name Maxwell as his last name.
When Duo was twelve, he stowed away on a ship, only to be discovered by Doctor G. Duo introduced himself with his famous "Duo Maxwell, who may run and hide, but never tells a lie." Doctor G takes in Duo as his apprentice.
Duo later was brought into the rebels, and given the piloting rights to the Deathscythe. Duo opposed Operation Meteor, and attempted to destroy the Deathscythe. This tactic failed, and he was convinced by Doctor G to steal the Gundam instead. Duo succeeded in stealing the Gundam, and he headed towards earth.
After arriving on earth, Duo, using the amazing stealth of the DeathScythe, attacks a Mobile Suit manufacturing factory under the control of The Alliance, and then later attacks a group of Cancers led by Zechs Merquise to salvage another Gundam, the Wing Gundam. Duo saves the Wing Gundam, and, thinking he can use it for spare parts, deactivates its self-destruct mechanism and brings it to the surface. He then goes to an Alliance Military base, where he sees a young man, who turns ot to be another Gundam Pilot named Heero Yuy, threatening a woman, who is actually Relena, at gun point. Before Heero can shoot Relena, Duo shoots the man in the arm, disarming him. Heero then attempts to get his gun, but Duo shoots the other pilot again. Before Duo can finish off the other Gundam mPilot though, Relena Steps in the way, asking Duo why he wants to shoot Heero. This confuses The gundam Pilot, since all he was doing was saving Relena from being killed by Heero. Before he can do anything else though, the Wing Gundam begins to come up from the sea. Duo blinds Relena with a bright light, telling her to be careful, or he'll have to kill her. Heero is able to take this oppurtunity to launch torpedoes he had set for the Wing Gundam, and Duo is unable to stop the man from firing the torpedoes at the Gundam.
Duo's Gundam is built for hit and run operations. The Gundam is armed with "hyper jammers" located on the back section of the mobile suit. The hyper jammers transmit a frequency that blocks all communications within a designated radius, these hyper jammers also project an "invisibility cloak that to almost all detection, invisible.
The Deathscythe was destroyed during Duo's attempts to reach outer space. Duo was forced to abandon his suit and flee back to his home colony. But during a training exercise Trowa piloting the "OZ-13MSX1 Vayeate" shot it down. Duo eventually was captured on his home sweeper colony by an OZ soldier piloting Wing Zero. Duo with Wu Fei were eventually broken out of incarceration by the group of professors who had build the gundams and upgraded Nataku and Deathscythe. Deathscythe had attained a new level of power which employed a newly improved set of hyper jammers, a magnetic defense unit concealed within the wings, and a twin scythe equipped with boosters for enhanced power.
In other media the Deathscythe appeared in the movie "Gundam Wing Endless Waltz". The Deathscythe was refurbished and took on a totally new design sporting new larger wings, and a new set of armor colors and plating. The twin scythe was replaced by a larger death scythe with only one beam. This new scythe's beam in fact was considerably larger though.