Captain Marvel is the name of several superheroes in the Marvel universe. The original Captain Marvel was Mar-Vell, and the current incarnation of the character is Carol Danvers.
The original Captain Marvel was Mar-Vell, an alien Kree operative sent to observe Earth, but who became inspired by its people and became their protector. After he died of cancer, he was succeeded by Monica Rambeau, who acted as the second Captain Marvel within the Avengers. Genis-Vell, the genetically engineered son of Mar-Vell, became the third Captain Marvel. His sister, Phyla-Vell, became the fourth, eventually becoming associated with the Guardians of the Galaxy. Carol Danvers, the former Ms. Marvel, is the current Captain Marvel.
In the Marvel Cinematic Universe, Captain Marvel is portrayed by McKenna Grace and Brie Larson.
