Kazuya is part of the game's second Fighters Pass, which includes Arms' Min Min, Minecraft's Steve & Alex, Final Fantasy VII's Sephiroth, and Xenoblade Chronicles 2's Pyra & Mythra. The Fighters Pass cost US$29.99 and it will include six different characters, two of which are yet to be revealed. You can also purchase each brand new individual character for US$5.99. Aside from the new character, the DLC will also include additional music and a brand new stage.
More details about Kazuya will be revealed by Super Smash Bros. director Masahiro Sakurai in a special character showcase on June 28th at 7am PT.