The Flash is the fastest man alive. The protector of Central City and Keystone City, fighting against evil using his super-speed and a dedicated sense of heroism. His legacy, the Flash Family, spans throughout history tapping into the enigmatic Speed Force to gain their powers. Jay Garrick was the original Flash of the Golden Age, and a founding member of the Justice Society of America. Barry Allen was the Flash of the Silver Age and a founding member of the Justice League of America. He sacrificed himself to save the universe during the Crisis on Infinite Earths, but was resurrected during Final Crisis. His replacement was Wally West, his nephew and the original Kid Flash, formerly of the Teen Titans. The fourth was Bart Allen, who started his career as Impulse.
The Flash was created by Gardner Fox and Harry Lampert in his original incarnation. He first appeared in Flash Comics #1 (1940). The modern version was created by Robert Kanigher, John Broome and Carmine Infantino, first appearing in Showcase #4 (1956).
In the game, the Flash is voiced by Charlie Schlatter, who had previously voiced the character in LEGO Batman 3: Beyond Gotham, and various other media.
Schlatter also voices Kai, in place of Vincent Wong.
His appearance is reused from LEGO Batman 3: Beyond Gotham.
During E3 2015, many spherical models symbolising various worlds displayed a variety of characters interacting with one another. The Flash appeared in the Back to the Future sphere, though it is unknown why he appeared, due to his lack of a physical character appearance in a LEGO Dimensionsset.
Because of this, it was speculated that he may have originally been planned to be a playable character. It was confirmed that he was originally planned to be released in Year 3, but was scrapped as Year 3 ended up being shelved entirely due to the lacklustre sales of Year 2 content.
The Flash appears at the "57th Annual Justice League Anniversary Party" at the Fortress of Solitude. He asked Batman if he could take a picture of the entire Justice League, which everyone but Batman appear in. A few seconds later, he can be heard thanking Batman for taking the picture.