Robert Long was the child of Donna Troy and Terry Long.
He was born with great powers, but those powers would have made him power hungry in the future. Future Titans came to kill Donna before she could give birth to him. Lord Chaos also came to ensure his birth and future. Donna gave birth to Robert and with the help of both her team and the future team defeated Lord Chaos. Donna then asked the Titans of Myth to take away her powers and her sons, to make sure he never became Lord Chaos.
Donna and Terry divorced and Terry got sole custody of Robert. Robert Long died in a car accident with his father and step-sister at the age of three.
Lord Chaos' legacy could be seen 10 years in the future – in an alternate timeline where Chaos ruled the Earth.
It all began when Donna Troy, who was gifted with godlike powers, gave birth to a son. Her child was born completely sentient. With his godlike powers, he instantly aged himself and killed his mother. Over the next few years, Chaos' power spread. Slowly and effectively, he conquered the world.
Chaos created an army of storm troopers whom he dubbed his Force Elite. They kept control of Chaos' world – enslaving or killing all who would oppose him. He crushed any resistance and created a food additive called numb dust, which drugged the worlds' population into submission. Only Chaos would soon discover that the same dust would have an unexpected consequence; it affected the hypothalamus. It produced altered hormones. One in every million babies was born with a metagene.
Chaos panicked over the thought of super-powered enemies. So the children were taken from their parents and raised by his scientists to fight for him against everyone else.
Only one force of rebellion stood as a threat against him: The Team Titans. Inspired by the legend of the Titans, a mysterious leader led a group of rebels to oppose Lord Chaos.
The Team Titans leader gave the team a mission: travel ten years into the past to stop Chaos from ever being born. To accomplish this, the Teamers were assigned to kill Donna Troy before she would give birth to the child who would become Lord Chaos! The Teamers successfully traveled to the past and came into conflict with the Titans.
At the same time, Chaos emerged in the past to insure he would be born. Chaos battled both Titans teams and was able to prevent the Team Titans from killing Donna Troy. Robert Long was born, and Chaos believed his victory was assured. However, the Titans of Myth intervened, and stripped the baby of his godlike powers. They also took Lord Chaos, the "false seed; the child whose future has been altered and should never have been". The Titans of Myth absorbed Lord Chaos to make him learn humility. In their words, "He is with us now. He will learn, or he will cease to be."
During the time crisis known as Zero Hour, it was revealed that the Team Titans future was a false timeline created by Extant. During the Zero Hour event, time continued to collapse, erasing the 'false' timelines that had emerged. As a result, Lord Chaos may have ceased to exist.
For more information see: Blackest Night
Robert (still an infant) and Terry Long are resurrected by Black Lantern Rings, and join in the assault of Titans Tower to torture and feast on Donna. Donna at first believes they are back from love, and that her family is reunited and hugs her son. Robert then bites Donna's neck, infecting her with Black energy. As Robert and Terry are about to feast on her, Bart manages to run in and save Donna, then returns her to the main room with Wonder Girl.
As they exam her bite, Black Lantern Terra recovers and creates an earthquake, sinking the Tower. As Robert and Terry follow along, Donna gathers her strength to fight them. As more zombie Titans storm the tower, Donna tells everyone not to believe anything they say, and don't hold back. She then angrily crushes Robert's head. Terry and Robert are about to feast on her, while Black Lantern Hawk (Holly Granger) corners Dove, ready to tap into the mysterious white energy inside her. As Hawk grabs her to steal her heart, Dove begins to emit White energy, destroying Holly. Robert, Terry and the other Black Lantern Titans realize Dove is now the bigger threat. Dove unleashes a White Blast, killing all the Black Lanterns except Hawk (Hank Hall), Tempest and Terra.
Robert Long no longer has any powers as they were sealed by the Titans of Myth.
As Lord Chaos, he possessed vast godlike powers, including powerful fire-blasts, flight, and teleportation, as well as unbelievable strength and durability as well as immortality.
In Kingdom Come Robert took over Donna's role as the superhero named Darkstar. At one point Darkstar appeared in Titans V1 along with the other sons and daughters of The Titans to help Donna Troy when she was once again wiped from memory and had the other Titans turn on her. Once this was complete they returned to their own time. It is uncertain as to whether their universe was destroyed and still exists in the New 52.