To unlock new arenas, complete the challenges listed below:
Lakeside Coliseum:beat stage 3 of chapter 1 in weapon master mode.
Money pit:beat stage 1 of chapter 4 in weapon master mode. Labyrinth:beat stage 6 of chapter 6 in weapon master mode.
Hwangseo palace/Phoenix court:beat stage 2 of chapter 7 in weapon master mode.
Egyptian Crypt: beat stage 5 of chapter 8 in weapon master mode.