The Fastest Lion is a slender lion, with light-brown fur and a dark-brown stripe that is running down his back. He has a reddish-brown nose and his eyes are brown. Above his eyebrows, he has some cream-colored fur lining. The tip of his tail is light brown.
Nothing is known about them. But as he is the Fastest of Scar's Guard, you can assume that he can run really fast and endure long distances without a problem. As a member of the Lion Guard, he was devoted to protecting the Pride Lands and the Circle of Life, that he refused the order of his leader, Scar, to aid him in usurping Mufasa.
The Fastest Lion was born in the Pride Lands under the rule of the Lion King and Queen at that time. At some point either in his childhood, or his adolescence, he was chosen by Prince Askari, Prince Mufasa's younger brother as the fastest member of the Lion Guard.
Sometime during Mufasa's reign as King, Askari was bitten by a cobra, and nicknamed Scar by his older brother, a nickname which he would soon accept as his name. As a result of Mufasa's mockery of him, Scar ordered the Lion Guard to help him kill Mufasa. However, when they refused, Scar used the Roar of the Elders to kill them all, ending his time as leader of the Lion Guard, as well as the Lion Guard's legacy on the Pride Lands.