souls can also be spent to permanently transform a character's weapon. at yoko belnades' shop, the player can remove certain souls from their inventory to change their weapon into a stronger form. certain weapons can only be acquired by using souls to strengthen a lesser form of the weapon. souls are also used in the "enemy set" mode, where a player builds a custom scenario. the player can place monsters inside rooms if they have acquired the monster's soul in the main game, but boss enemies cannot be added to any scenario, even if the player has the boss' soul. two players using two nintendo ds consoles can compete in these scenarios, with the winner being the one with the fastest time completing the course.