Mortal Kombat: Deception is a fighting game developed and published by Midway as the sixth installment for the Mortal Kombat(MK) series. It was released for the PlayStation 2 and Xbox in October 2004, while a Nintendo GameCube version was published in March 2005. Mortal Kombat: Deception follows the storyline from the fifth installment, Deadly Alliance. The story centers on the revival of the Dragon King Onaga, who attempts to conquer the realms featured in the series after defeating the sorcerers Quan Chiand Shang Tsung, the main antagonists in the previous game, and the Thunder God Raiden, defender from Earthrealm. As such, the surviving warriors from the previous titles join forces to confront Onaga.
Twenty-six characters are available to play in the game, with nine making their first appearance in the series. Deception contains several new features in the series, such as chess and puzzle games with the MK characters and an online mode. The Konquest Mode role-playing game (RPG) makes a return from Deadly Alliance, but follows the life of Shujinko, a warrior who is deceived by Onaga to search for artifacts to give Onaga more powers. In November 2006, Midway released Mortal Kombat: Unchained, a port for the PlayStation Portable, which adds new characters to the game.
Series co-creator Ed Boon designed Deception to be an unpredictable fighting game, and included new features such as the mini-games as surprises. Several parts from Deadly Alliance such as combos and arenas were redesigned to be more realistic as well as more interactive. Deception has been well received by video game reviewers, who praised the fights and new features. The Konquest Mode, however, received criticism for poor voice acting. Several publications have awarded the game as the best fighting game in 2004.