Doctor Light is a supervillain who uses light powers.
Doctor Light is a member of the expanded Justice League.
There are two versions of Doctor Light. One has light powers, and the other also has light powers. They're a boy and a girl, and a villain and a hero.
Dr. Kimiyo Hoshi was an astronomer and became a hero during the Crisis when the all-powerful Monitor zapped Dr. Hoshi with otherworldly energy. Her new power allowed her to control and absorb a variation of different light energy. After the Crisis Hoshi dawned a costume and joined the Justice League calling herself Doctor Light and even became the team leader of the European branch. Doctor Light was arrogant and left many of her teammates with a cold feeling about her.