By pressing the Rave Button ( by default), when a player is in Beast Form, he can enter into his Beast Rave Form. The character will, then, be flashing with yellow light and thunders during the remaining time of the transformation.
In Rave, the fighter sees a general speedup and most of his attacks recovery will be greatly reduced giving him the opportunity to link more easily his attack and strings.
This transformation is limited in time, as, once the Rave activated, the Beast meter will slowly decreased. When the beast gauge is empty the Rave is cancelled and the fighter come back to his human form.