Battle Points. You get five and they limit how often you can attack in a campaign. They retore themselves after 45 minutes or so. You get a "first time attack" for free then any time you want to attack after requires using up your BP. You get three choices on how to spend your BP. You can use one and do a regular attack, use 2 and have x2 the attack power, or 3 and and do x4 the attack power.