K′ (ケイ・ダッシュ, Kei Dasshu, "K Dash"), sometimes known as "K Prime", is a character who debuted as the leader of the Hero Team in The King of Fighters '99. He stars as the reluctant hero in the NESTS saga of the series, often letting his partner Maxima handle any social necessities in his stead. To contrast the previous protagonist of the series, K' was made to be the "dark hero". In a 2005 poll made by SNK-Playmore USA, he was voted as the fourth fan favorite character with a total of 338 votes.
The origins of both K′ and Maxima can be found in the Psikyo arcade game The Fallen Angels (Daraku Tenshi in Japan). This obscure 1998 release stars an emaciated goth in tight leather pants named Cool, along with a brawny, cybernetically enhanced police officer named Harry Ness. The man responsible for the design of both characters, Shinichi Morioka, migrated to SNK shortly after The Fallen Angels was released, and elements of Cool and Harry Ness' design were used in the creation of K′ and Maxima. The end result is that K′ looks nearly identical to Cool. His namesake was taken from a clone character in the light novel, Blue Knight Beluzaga Monogatari, which is set in the same universe as the anime, Armored Trooper Votoms. During the early phases of development of The King of Fighters '99, K′'s introduction to the series was meant to remove popular characters Kyo Kusanagi and Iori Yagami from the roster -though this idea was scrapped in the game's release.
He is voiced by Yuuki Matsuda and Andrew Scott.
K' sticks to the same design in every game. He has white hair, hazel eyes and tanned skin. He also wears a full shiny leather ensemble that consists of a black leather jacket, leather pants, and a red glove that controls his fire.