Bart Allen

In DC Comics continuity Bart Allen is born in the 30th century as a descendant of the Flash legacy (grandson of Barry Allen on his paternal line and related to Thawne descendants on his maternal side). Due to his connection to the Speed Force he undergoes accelerated aging and is raised in a virtual reality environment that matches his subjective sense of time to prevent mental-health problems. He is taken to the 20th/21st century where he adopts costumed identities (Impulse, later Kid Flash and briefly the Flash), serves on teen teams (Young Justice, Teen Titans), is trained/mentored by senior speedsters (Wally West, Max Mercury, Jay Garrick), dies in one arc and is later resurrected in subsequent cross-title storylines involving the Speed Force and alternate timelines.

Sources depict Bart as a male youth with an athletic, teenage appearance; early in his public career he appears roughly twelve years old as a result of rapid aging despite being chronologically much younger. In publication he is visually presented in costumed identities associated with his aliases (Impulse, Kid Flash, The Flash) and has been portrayed in adaptations by youthful actors; detailed costume descriptions are specific to individual comics and media adaptations but the core visual signifier is the speedster costume associated with the Flash legacy.

Bart's core ability is Speed Force-derived super-speed: running at extreme velocities, high metabolic/temporal effects (rapid aging), creation of Speed Force energy duplicates, and interaction/absorption into the Speed Force. In some storylines he can steal or redirect speed from others (e.g., Titans Tomorrow/alternate timelines). He has used speed offensively in combat, and in major crossover events participated in actions that pushed or routed adversaries into the Speed Force (for example, running Superboy-Prime into the Speed Force with assistance from other speedsters). His physiology and behavior are shaped by accelerated tempo (rapid metabolism and aging) and by the social consequences of a childhood spent in simulated time.