Wally West is: THE FLASH

The Comic Relief of the League, when Wally was only 7 years old, he was kidnapped by the villain Turtle, to be used as bait to lure his uncle, Barry Allen, the second Flash, so that the villain could steal his powers. When the energy extraction machine overloads with Barry's powers, a huge explosion occurs, which kills both Barry and the Turtle, leaving only Wally alive. The rest of Wally's childhood and adolescence were completely normal, until on his 17th birthday, Barry's powers that had been transferred to him that night finally manifested themselves. Wally then began using a makeshift costume to fight crime, but the villains did not take him seriously at all, nicknamed him Kid Flash. Tired of the mockery, Wally decides to abandon his homemade costume and use his uncle's old costume, with some modifications made by himself, thus becoming the third Flash.