Toaru Majutsu no Index is a fighting game based on the Toaru Majutsu no Index universe. The game features an original story by the author of the series, Kamachi Kazuma. As with many fighting games, players choose a characters from a lineup, and engage in hand-to-hand combat with an opponent. It is primarily a competitive two player series, but a human player can fight an AI-controlled character for practice, amusement, or to advance the game's story. In the game the player has the option of using a partner to be used as support during the match. All the characters can be used as partners, however, both Index and Last Order are exclusively partner-type characters, and can't be used for fighting.