The Chain Bonus, Chain Gauge and ability to Stagger enemies are the two key aspects of combat in Final Fantasy XIII that need to be understood in order to maximize the efficiency of your characters and the battles you engage in. So what are they?
There is an in-game provided explanation in the early chapters that helps shed some light on how this concept works. But there are two important percentages that you should always keep track of:
The last thing you should always be keeping an eye on is the bar above those two percentages which is the Chain Gauge. If it drops all the way to the left the Chain Bonus will be reset to 100% and you will have to start again. Most of the battle strategies you will encounter throughout this guide and as you progress through the game involve trying to get the Chain Gauge up to the Stagger Point to Stagger the enemy.
When an enemy is Staggered, the Chain Bonus will take an immediate jump, effectively causing all subsequent attacks to deal significantly higher damage. Additionally, most enemies will be prevented from doing certain attacks while they are Staggered. Therefore, the goal of most fights is to get an enemy to their Stagger Point and then pump out as much damage as possible before the Stagger runs out and their Chain Gauge is reset.
The maximum Chain Bonus that you can obtain is 999% and there are certain fights you will encounter where getting up to this maximum value will be a necessity.
Many of the roles that are available to your characters serve important roles in helping you manage the Chain Gauge and attempting to Stagger an enemy. More information can be found in the Paradigms and Roles sections of the guide, but at a basic level, these are the most important elements to note:
Ravagers are one of the damage dealing classes and their attacks will increase the Chain Gauge the most.
Commandos are the other damage dealing classes and, while their attacks do not fill the Chain Gauge much, their attacks prevent the Chain Gauge from dropping as quickly preventing a potential reset.
Sentinels and 
Saboteurs are capable of preventing the Chain Gauge from dropping as well but they are less effective at this than Commandos. It’s also important to note that if you are not controlling a Saboteur and all of the debuffs have been applied, the computer controlled Saboteur will stop casting altogether.
For more information on the specifics of the different roles and paradigms, use the navigation menu to go to the Paradigm and Role pages.
