While we still have no idea what the hell Metal Slug Attack is, we’ve gotten word that SNK Playmore is adding a King of Fighters collaboration into Metal Slug Defense, in celebration of the series’ 20th anniversary.

For those unaware of what Metal Slug Defense is, it’s a free-to-play iOS and Android game that is more of a tower defense than a true Metal Slug game, mostly to adapt the game to a more mobile-friendly format.

The new King of Fighters characters (featured above) will be available in Metal Slug Defense beginning on May 1st of this year. The confirmed fighters so far are Kyo Kusanagi, Benimaru Nikaido, and Goro Daimon.