Ultraman King is one of the oldest and most powerful Ultras in the history of the Ultraman Series, having been alive for quite some time before the construction of the Plasma Spark that turned the Residents of the Land of Light into Ultras. With his age, knowledge and miraculous powers, King is a greatly revered figure in the World of the Land of Light, and perhaps throughout the Multiverse.

Despite the name, he is not the king of the Land of Light and he observes the events of the universe (and beyond) while meditating on a planet where only he lives, though his true home world is unknown. "King" is also not his original name, as he stated that is the name humanity gave him and that he has had many from many races across the universe.

A legendary Ultraman from the Land of Light, King was alive before the creation of the Plasma Spark. He is extremely powerful in the appearances he has made, showing he is able to bring Ultraman Leo back to life after he'd been sawed to pieces by Black Directive without any effort. His age was revealed to be 300,000 years in the 2003 movie New Century 2003 Ultraman.