Ryuki Kajita (Japanese: 梶田隆基; born: October 14, 1987), better known online as マフィア梶田 (English: Mafia Kajita), is a Japanese columnist, radio MC, voice actor, and male actor affiliated with 4Gamer in Japan.
He was born in Shanghai, China but his school life was mainly connected with Japanese culture.
He joined YouTube in 2011 but mostly hosts in other Japanese gaming media channels.
Because of his costume style similar with his current penname "Mafia", modelkasten and Good Smile Company respectively produced different figures with his personal "Mafia" image.
On March 5, 2020, he and Yuichi Nakamura jointly created a game-streaming channel named "Mafia Kajita and Yuichi Nakamura's WasyaganaTV" (Japanese: マフィア梶田と中村悠一の「わしゃがなTV」) supervised and directed by 4Gamer.