Nightstar is the daughter of the Titan couple Nightwing and Starfire. When she was a child she worried constantly about her parents, especially after realizing that all of her biological grandparents had died in tragic ways.
Major Story Arcs
When Starfire died, she became distant from her father and started to be more attached with Bruce Wayne, joining his Outsiders. After the events of Kingdom Fire she began to reconcile with her father.
During the Kingdom storyline, we learn that she's dating Ibn al Xu'ffasch, Batman's son, and that she used to work at Alan Scott's space station, The Green.
She later re-appears during the Titans arc "Who is Donna Troy?", traveling back in time with her team of Titans to help Donna Troy fight Dark Angel.
Nightstar was created by Mark Waid and Alex Ross. Her first appearance was in Kingdom Come #1, May 1996.
Powers and Abilities
Nightstar can fly, absorb and project energy, and has enhanced strength - products of her Tamaranian/Human physiology.