Kimiyo Hoshi, the heroic female Doctor Light in DC Comics, first appeared in Crisis on Infinite Earths #4 (July 1985), created by Marv Wolfman and George Pérez. A brilliant Japanese astronomer and physician, Hoshi was observing a cosmic disturbance when a energy beam from the Monitor struck her, granting photokinetic abilities derived from the Vega star system's energies during the multiversal crisis. Initially arrogant and dismissive of other heroes, viewing them as distractions, she adopted the name Doctor Light after confronting shadow demons unleashed by the Anti-Monitor, distinguishing herself from the villainous Arthur Light while establishing her role as a formidable ally in the battle to save reality.

Doctor Light possesses extensive photokinetic powers, enabling her to absorb, generate, and manipulate light across the electromagnetic spectrum, including ultraviolet and stellar energies. These abilities allow for flight at near-light speeds, creation of solid light constructs and force fields, energy projection in devastating blasts, illusions, invisibility, and enhanced strength when charged. Her scientific expertise complements these powers, permitting precise control and innovative applications, such as draining light sources from opponents or achieving interstellar travel in light form, positioning her among the Justice League's most versatile energy manipulators.

Hoshi's character evolved through membership in Justice League Europe and International, where her intellect and initial aloofness created interpersonal dynamics, later softening into dedicated heroism. She briefly joined the Doom Patrol, experienced temporary power loss due to cosmic events, and navigated personal life as a divorced mother of two while maintaining her scientific career. Post-New 52 continuity reintroduced her in arcs like Forever Evil and Justice League stories, emphasizing her resilience against threats including the Crime Syndicate and personal confrontations with Arthur Light, solidifying her legacy as a principled counterpart to the name's villainous associations.