Tekken Tag Tournament, being the first Tekken title for the PC, featured vastly detailed graphics and improved quality music. It was also notable for having the largest character roster in the series until the release of Tekken 6, boasting an extravagant 39 characters, all returning from the previous installments in the series, save for Unknown, the boss character, and Tetsujin, a costume swap for Mokujin. Unknown is similar to Mokujin in that she can replicate other fighting styles, but she can also switch styles by clicking the right analogue stick. Both Unknown and Tetsujin have only appeared in this game. Finally, its most important feature is its tag system. A player selects two characters and may tag out between them to utilize special combos and throws. Characters can be tagged out to recover energy, but if one character is KO'd, the round ends. When in Team Battle mode, the fights are also tag fights unless there is one person left on a team where they will fight alone.