Doctor Fate is Kent Nelson, a sorcerer and superhero.
First appearing in his own self-titled short comic strip in National Allied Publications' (later renamed DC Comics) More Fun Comics #55 (May 1940), Doctor Fate was first created by writer Gardner Fox and artist Howard Sherman. Doctor Fate is the costumed identity of one of the most powerful magical guardians and defenders of the realm of Earth from the supernatural and the Forces of Chaos.
Over the decades, a succession of individuals have borne the mantle including Kent Nelson, Eric and Linda Strauss, Inza Nelson, Jared Stevens, Hector Hall, Kent V. Nelson, and currently Khalid Ben-Hassin.
Gifted with the powerful Amulet of Anubis, the Cloak of Destiny, and the Helm of Nabu; these potent mystical artifacts transform the wielder into one of the world's most accomplished sorcerers in the world. The various versions of Doctor Fate has also served alongside other champions of humanity including the All-Star Squadron, the Justice Society of America, the Justice League, and the Sentinels of Magic.
But while the person may change, the one constant behind the guise of Fate is Nabu, a Lord of Order who now resides in the golden helmet as a disembodied spirit. When the current wielder dons the Helm of Nabu, he "possesses" their physical form which functions as his earthly avatar and allows him to channel his awesome mystical powers through them. On occasion, Nabu has simply functioned as an advisor, whispering spells or information to the current Champion of Fate.