Nightstar first appears as a cameo in Kingdom Come, Issue #1, where she lives in a world where most of the DC super villains have either died or disappeared, and where several DC superheroes have turned rogue. Her father Nightwing and his adoptive father Bruce Wayne/Batman are at odds with each other, especially after the latter forms an alliance with Lex Luthor.
During the course of the series, Nightstar encounters Batman's son Ibn al Xu'ffasch, where the two form a brief romantic relationship.
Eventually, Lex Luthor discovers Batman's true agenda and plans to unleash chaos onto the world. As a result, Batman and Nightstar, alongside their followers easily overpower Luther and foil his plans.
Afterwards, the Justice League constructs a prison designed to hold rogue super humans, but soon after its completion, it is breached, causing a battle to ensue between the League (and later Batman's Outsiders) against the prisoners. During the battle, Nightstar briefly fights Green Lantern. Eventually her father is seriously injured in the battle and out of shocking safety, she flees. When the battle ends, Bruce Wayne's manor is converted into a hospital to treat the injured superhero, during which Nightstar's father and grandfather reconcile.
Nightstar plays a major role in the The Kingdom series (the sequel to Kingdom Come), where her real name is revealed to be Mar'i. She takes up the role of the leader of her generation of the Teen Titans, a role once held by both of her parents.
Nightstar shares a near-identical resemblance to her mother, having green eyes that are pupilless and wearing a similar outfit. However, she inherits her father's black hair and paler skin.
Nightstar shares the same identical powers as her mother. She can fire green, solar-energy blasts or "starbolts" from her arms, can fly through space at roughly the speed of light, and has super-human strength.