you can use 4 at a time well sorda, i mean when you have a guest theres 4 people out, i really like that and that they dont take up any space on your team and they got unlimited items, and if your able to pull off all 9 quickenings when you get them all you can knock out a boss like noproblem i did it by accedent and he died i got kinda mad since i didnt see what he's able to do for future playing..but it was kinda funny, and Bizerk quickenings are a new addition to final fantasy like overdrives or sumthing, but here you are able to create a chain with all the characters thats out on the field and create massive damage, but i would request not to do any quickenings intill you got atleast 3 available quickenings at your disposal because only doing 1 quickening is a waste of mp, and i like this fight style much better because here you get to choose not to fight and you can always wonder at your own will, and you can always be ready to fight since you get to choose to attack or not as long as the enemy doesnt see you.