You are able to research different roles in the Crystarium, with certain roles being available earlier for different characters. Each role has a number of abilities to make your character more effective. Depending on the character's stats, including boosts from weapons and accessories, and the abilities available to them, certain people are better suited for specific roles. When choosing roles for your characters, keep in mind their stats, available abilities, who they'll be partied with and their roles (for efficient paradigm decks), and your long term goals.
Every time you reach another role level in the Crystarium, that character gets a boost for that role. The boosts are different for each role, and generally boost the character who attained the higher role level a lot and then other allies in battle a little bit. This is one reason why it's good to have a long term game plan for how you're going to developer your characters, because they become much more powerful at higher role levels.
Commandos are the heavy hitters of the game. They do great amounts of damage and have abilities to interrupt enemy attacks and knock them into the air so they're immobilized. The Commando's greatest asset is strength, and in this department Fang is the best. Snow is also very strong, as is Lightning, but the former has one less ability than Fang and makes a better Sentinel, and the latter is much weaker and missing even more Commando abilities. Besides their great attack power, Commandos can slow down the rate that an enemy's chain gauge depletes and they direct Ravagers so they are attacking the enemy. The combination of Ravagers and a Commando, quickly boosting up the chain gauge and then slowly its decay, respectively, is the most reliable way to stagger an enemy. Commandos mainly use physical attacks, and will move to far away or moving targets, though they do have the option to use Ruin if an enemy is airborne, moving too fast or resistant to physical attacks.
The Commando's job is a simple one compared to some of the other roles, so it's a great role to give the party leader, as that's one you'll be controlling. The AI does exactly what you would do as a Commando using the auto-attack option. A good pairing with a Commando is a Sentinel who will keep the attacks away from you, freeing you to do as much damage as possible without being interrupted.
|Powerchain||Auto||Yes||Yes||No||No||Yes||Yes||Increases the damage of the Commando's first blow when the enemy's chain gauge is empty.|
|Lifesiphon||Auto||Yes||Yes||Yes||No||Yes||Yes||Regain an ATB segment for every enemy killed with a single attack.|
|Faultsiphon||Auto||Yes||No||Yes||Yes||No||Yes||Slightly charge ATB gauge when attacking status-inflicted enemies.|
|Launch||Auto||Yes||No||No||No||Yes||Yes||Launches a staggered enemy into the air, preventing them from attacking until they descend.|
|Ravage||Auto||Yes||No||Yes||No||Yes||Yes||Bonuses Ravagers' chain building and Commandos' chain maintenance.|
|Smite||Auto||Yes||No||No||No||Yes||Yes||Increased damage for attacks landing just before an enemy comes out of a stagger.|
|Blindside||Auto||Yes||No||No||Yes||Yes||Yes||Increased damage for an attack on a non-staggered enemy who isn't targeting someone with the Blindside ability.|
|Scourge||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Increased damage for attacks landing just before an enemy comes out of a stagger.|
|Jeopardize||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Boosts the chain percentage increase when attacking a staggered enemy.|
|Deathblow||Auto||No||No||No||Yes||Yes||Yes||Instant death when attacking an enemy with sufficiently low HP.|
|Adrenaline||Auto||No||Yes||No||Yes||Yes||Yes||Increases the Commando's strength and magic when HP is high.|
|Attack||1||Yes||Yes||Yes||Yes||Yes||Yes||Basic attack, modified by circumstance by the auto abilities. Damage based on the strength stat.|
|Blitz||2||Yes||Yes||Yes||No||Yes||Yes||Area-of-effect attack that hits all enemies within range.|
|Ruin||1||Yes||Yes||Yes||Yes||Yes||Yes||Alternative magical attack for when a physical attack isn't useful.|
|Ruinga||3||Yes||Yes||Yes||Yes||Yes||Yes||Stronger version of Ruin, this attack has area-of-effect damage and can interrupt enemies.|
|Highwind||All||No||No||No||No||No||Yes||Fang's unique, super-powered attack based on the current chain percentage. Depletes chain gauge upon use.|
|Sovereign Fist||All||No||No||No||No||Yes||No||Snow's unique, super-powered attack based on the current chain percentage. Depletes chain gauge upon use.|
Medics have the simplest jobs of any role—just restore allies' health or bring them back to life if they get knocked out. Unless you're fighting very strong opponents, try to use paradigms with Medics in them as little as possible so you can keep inflicting damage. You'll also want to be careful to switch out of a healing paradigm quickly if everyone is fully healed with no status ailments, as the AI Medic will just sit there doing nothing. Both Hope and Vanille can perform all Medic abilities, and they both have excellent magic stats, so are the best suited for the job. If one of them isn't available, try to use Lightning or Fang in this capacity, as they are the other characters that can use Raise. The effectiveness of a Medic's abilities is based on their role level and magic stat.
The AI Medic will attempt to heal allies with health bars in the red before ones in the yellow, and ones in the yellow before ones in the green. If all else is equal, the Medic will attempt to heal the party leader first, then themselves. They will also heal low health first, then raise knocked out allies, then remove status ailments. In some cases it is better to use a Synergist to cast the opposite of a status ailment on an ally rather than waiting for the Medic to use Esuna. The nice thing about using the AI Medic is that they will automatically use the least expensive spell to get the job done. In other words, they'll use one ATB segment of Cure if that's all it takes.
|Cure||1||Yes||Yes||Yes||Yes||Yes||Yes||Replenishes some of an ally's health.|
|Cura||2||Yes||Yes||Yes||Yes||Yes||Yes||Replenishes some of allies health within an area-of-effect.|
|Curasa||1||No||Yes||Yes||Yes||Yes||No||Replenishes a lot of an ally's health when their health is low, but less when it gets higher.|
|Curaja||2||No||No||Yes||Yes||No||No||Replenishes a lot of allies' health in an area-of-effect when their health bars are low, but less when they higher.|
|Esuna||2||Yes||Yes||Yes||Yes||Yes||Yes||Removes an ally's most recent status ailment.|
|Raise||3||Yes||No||Yes||Yes||No||Yes||Brings an ally back to life and gives them a small amount of health.|
Ravagers are an essential part of building an enemy's chain gauge up. They rely mostly on magic attacks, with the exception of the "strike" abilities and the unique abilities like Army of One, Cold Blood and Last Resort. Because this role is based heavily on the magic stat, it's good to research this role with a character that has high magic and is also researching another magic-based role like Medic, Saboteur or Synergist. Characters in those roles usually don't stay in them exclusively, so you'll want a damage-dealing role for the paradigms you switch to between them. For the pure Ravager specialist, Lightning is your best choice. Not only does she have access to nearly all the Ravager abilities, but she has very high magic and strength, though not enough to be the best Commando or Sentinel. Hope is another good choice, as he has the area-of-effect spells Lightning is missing and tons of magic.
When the AI plays the Ravager role, it will target whichever enemy you're targeting as the leader to quickly build up its chain gauge. Because the Ravager's abilities are mainly element-based, you'll want to make sure your enemies are scanned so the AI can queue up the proper attacks. A Synergist can greatly boost the efficiency of your fights by buffing a Ravager's elemental attack even further against an enemy already weak to that element. In addition to Ravagers in your party, you'll also want to have either a Commando or Saboteur to slow down the decay on enemies' chain gauges.
|Vigor||Auto||Yes||No||Yes||No||Yes||Yes||Boosts chain bonuses when the Ravager's HP is high.|
|Overwhelm||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Boosts chain bonuses for any character targetting the same enemy as the Ravager.|
|Fearsiphon||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Slightly charges ATB gauge when attacking a staggered enemy or enemies.|
|Fire||1||Yes||Yes||Yes||Yes||No||Yes||Magical fire attack.|
|Fira||2||Yes||Yes||Yes||Yes||No||Yes||Magical area-of-effect fire attack.|
|Firaga||3||No||Yes||Yes||Yes||No||No||Same as Fira, with increased range.|
|Blizzard||1||Yes||No||Yes||Yes||Yes||Yes||Magical ice attack.|
|Blizzara||2||Yes||No||Yes||Yes||Yes||Yes||Magical area-of-effect ice attack.|
|Blizzaga||3||No||No||Yes||Yes||Yes||No||Same as Blizzara, with increased range.|
|Thunder||1||Yes||Yes||Yes||Yes||No||Yes||Magical lightning attack.|
|Thundara||2||Yes||Yes||Yes||Yes||No||Yes||Magical area-of-effect lightning attack.|
|Thundaga||3||Yes||Yes||Yes||No||No||No||Same as Thundara, with increased range.|
|Water||1||Yes||No||Yes||Yes||Yes||Yes||Magical water attack.|
|Watera||2||Yes||No||Yes||Yes||Yes||Yes||Magical area-of-effect water attack.|
|Waterga||3||No||No||Yes||No||Yes||Yes||Same as Watera, with increased range.|
|Aero||1||Yes||Yes||Yes||Yes||Yes||Yes||Magical wind attack, with stun.|
|Aerora||3||Yes||Yes||Yes||Yes||Yes||Yes||Magical area-of-effect wind attack that launches enemies into the air.|
|Aeroga||5||No||Yes||Yes||No||No||Yes||Same as Aerora, with increased range and stronger upsweep.|
|Flamestrike||1||Yes||Yes||No||No||No||Yes||Physical attack inflicting fire damage.|
|Froststrike||1||Yes||No||No||No||Yes||Yes||Physical attack inflicting ice damage.|
|Sparkstrike||1||Yes||Yes||No||No||No||Yes||Physical attack inflicting lightning damage.|
|Aquastrike||1||Yes||No||No||No||Yes||Yes||Physical attack inflicting water damage.|
|Army of One||All||Yes||No||No||No||No||No||Lightning's unique ability, she pummels an enemy with multiple hits, drastically increasing the chain gauge and percentage.|
|Cold Blood||All||No||Yes||No||No||No||No||Sazh's unique ability, he pummels an enemy with multiple hits, drastically increasing the chain gauge and percentage.|
|Last Resort||All||No||No||Yes||No||No||No||Hope's unique ability, he pummels an enemy with multiple hits, drastically increasing the chain gauge and percentage.|
Saboteurs are on the other end of status effects from Synergists—instead of casting buffs on your party, a Saboteur will cast debuffs on enemies. Like all roles that involve status effects, it is very important to know the enemies' status weaknesses, resistances and attacks. In addition to debuffing the enemy, the Saboteur's abilities also inflict some magic damage and maintain the chain gauge like a Commando. The later effect is essential when you're lacking a Commando in your party to slow down the chain gauge's decay, or your Saboteur is also your Commando. Characters' access to abilities is all over the board, so you may want to train two complementary characters to have access to all the abilities. Vanille and Fang are great choices, as they start with the Saboteur role, they have different sets of abilities and Vanille is the only one that can cast Death.
Because it's complicated to try and figure out the status information yourself during battles, relying on the AI Saboteur is advantageous, as it automatically chooses debuffs based on the enemies' weaknesses and attacks. Besides casting spells to reduce an enemies resistance, Saboteurs can also remove enemy status enhancements. It is also good to train characters in this role as Ravagers, as that is also a magic-dependent role and you'll want to be able to inflict damage after switching paradigms when the enemy is full of status ailments.
Damage and chance of success for the Saboteur's abilities is based on a formula which modifies the base percentage of a given ability. In the table below, the base percentage rate of success is given, but you can increase the chance of success dramatically by influencing certain factors. The success rate is modified by the enemy's susceptibility to the status ailment, the current chain percentage, whether Vigilance has been cast on the Saboteur, the Saboteur's role level, whether the enemy is using Veil and any Improved Debuffing or Improved Debilitation properties on the Saboteur's weapon.
|Jinx||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Extends the life of an enemy's existing status ailments when new ones are added.|
|Deprotect||1||Yes||Yes||No||Yes||No||Yes||40% chance of reducing enemy's physical defense and inflicting magic damage.|
|Deprotectga||3||Yes||No||Yes||Yes||No||No||30% chance of reducing enemies' physical defenses and inflicting magic damage in an area-of-effect.|
|Deshell||1||Yes||Yes||No||Yes||No||Yes||40% chance of reducing enemy's magical defense and inflicting magic damage.|
|Deshellga||3||Yes||No||Yes||Yes||No||No||30% chance of reducing enemies' magical defenses and inflicting magic damage in an area-of-effect.|
|Poison||1||Yes||Yes||No||Yes||No||No||30% chance of inflicting poison on an enemy and doing magic damage.|
|Poisonga||3||Yes||No||Yes||Yes||No||No||24% chance of inflicting poison on enemies and going magic damage in an area-of-effect.|
|Imperil||1||Yes||Yes||No||Yes||No||Yes||30% chance of reducing the enemy's elemental resistance and doing magic damage.|
|Imperilga||3||Yes||No||Yes||Yes||No||No||24% chance of reducing enemies' elemental resistances and doing magic damage in an area-of-effect.|
|Slow||1||No||Yes||No||No||Yes||Yes||30% chance of slowing down the rate an enemy refills its ATB gauge and inflicting magic damage.|
|Slowga||3||No||No||Yes||No||Yes||Yes||24% chance of slowing down the rates enemies refill their ATV gauges and inflicting magic damage within an area-of-effect.|
|Fog||1||No||Yes||No||Yes||Yes||Yes||20% chance of disabling an enemy's use of magic attacks and doing magic damage to it.|
|Fogga||3||No||No||Yes||No||Yes||Yes||15% chance of disabling enemies' use of magic attacks and doing magic damage to them within an area-of-effect.|
|Pain||1||No||Yes||No||Yes||Yes||Yes||20% chance of disabling an enemy's use of physical attacks and doing magic damage to it.|
|Painga||3||No||No||Yes||No||Yes||Yes||15% chance of disabling enemies' use of physical attacks and doing magic damage to them within an area-of-effect.|
|Curse||1||No||Yes||No||No||Yes||Yes||20% chance of making an enemy more susceptible to interruptions and less able to interrupt your attacks, as well as inflicting magic damage on it.|
|Cursega||3||No||No||Yes||No||Yes||Yes||15% chance of making enemies more susceptible to interruptions and less able to interrupt your attacks within an area-of-effect, as well as inflicting magic damage on them.|
|Daze||1||No||Yes||No||No||Yes||Yes||30% chance of inducing stun on an enemy and dealing it magic damage.|
|Dazega||3||No||No||Yes||No||Yes||Yes||24% chance of inducing stun on enemies within an area-of-effect and dealing them magic damage.|
|Dispel||2||No||Yes||Yes||Yes||No||Yes||100% chance of removing the last status enhancement an enemy received.|
|Death||All||No||No||No||Yes||No||No||Deals magic damage and has a 1% chance of instantly killing vulnerable enemies.|
Sentinels won't seem very useful until you've leveled them up fairly high and have a lot of HP to expend. At earlier parts of the game, the Sentinel won't do much with the auto-attack except Provoke and Steelguard. Later though, this role becomes essential to draw fire away from vulnerable allies, allowing your party to either recover or inflict damage on a tough enemy without having to stop to heal. At very high levels, Sentinels can absorb huge amounts of damage and counter automatically, basically freeing you up to do anything from heal, attack, buff or debuff. The Sentinel's most important stat is HP, and Snow has the greatest potential for growth in that area. He also has access to the most abilities of any character except Fang, who has the same ones but lower HP.
As your main abilities are percentage-based, it's best to queue up multiple segments of a single ability to stand the best chance of success. Like Commando, this is a fairly simple role and a good one for the party leader so you can control the character. This has the added benefit of being able to direct your Challenges to higher priority enemies that the AI Sentinel might not pick.
|Evade||Auto||Yes||No||Yes||No||Yes||Yes||Sometimes dodge enemy attacks.|
|Counter||Auto||Yes||No||Yes||No||Yes||Yes||Sometimes counterattack after evading.|
|Deathward||Auto||Yes||Yes||Yes||No||Yes||Yes||Boosts physical and magical defense with low HP.|
|Fringeward||Auto||Yes||Yes||No||No||Yes||Yes||Reduces damage to allies from area-of-effect attacks targetted on the Sentinel.|
|Reprieve||Auto||Yes||No||Yes||Yes||Yes||Yes||Leaves 1 HP after a critical attack.|
|Provoke||1||Yes||Yes||Yes||Yes||Yes||Yes||45% chance of enticing all enemies to target you. Lasts for 50 seconds.|
|Elude||1||Yes||No||Yes||No||No||No||Raises probability of evading enemy attacks.|
|Challenge||1||No||Yes||No||No||Yes||Yes||99% chance of provoking a single enemy. Lasts for 150 seconds.|
|Vendetta||1||No||Yes||Yes||No||Yes||Yes||Counterattack after defending, with higher probability the more the Sentinel was attacked.|
|Entrench||1||No||No||Yes||Yes||Yes||Yes||Counterattack after defending, with higher damage the longer the Sentinel stayed defending.|
|Steelguard||1||No||Yes||No||Yes||Yes||Yes||Pure defense, with physical and magical resistance increasing the more the Sentinel is attacked.|
|Mediguard||1||No||No||No||Yes||Yes||Yes||Slowly regain HP while defending.|
Synergists have the ability to buff party members through status enhancements. Generally, it's best to use paradigms with a Synergist at the beginning of a battle to take advantage of the boosts for the longest amount of time. Status enhancements are only active for a limited time, so you may need to refresh them during longer fights. You can see the icon corresponding to the status on the left side of the character's health bar. Sazh is a great character for the Synergist role, as he has access to most of the abilities, including the important ones, and his stats aren't so great that you'll be missing him in another role. Boosting his magic stat to take full advantage of the role will also help him as a Ravager for when you switch paradigms when you no longer need status enhancements.
Like all roles involving status effects, it's very important to know your enemy's weaknesses, resistances and attacks. The AI Synergist is great, as it automatically queues up buffs based on what your enemy will be attacking with and what it is weak against, while avoiding useless buffs. Doing this yourself can be time-consuming if you have to constantly switch to the enemy info screen and try to decipher what will work yourself. If you know you'll be wanting a specific spell cast that the AI normally doesn't do, such as Veil or Vigilance, then you might want to control the Synergist yourself to cast them at the beginning of the fight.
|Boon||Auto||Yes||Yes||Yes||Yes||Yes||Yes||Extends the life of an allies existing status enhancements when new ones are added.|
|Bravery||2||Yes||Yes||Yes||No||Yes||No||Increases ally's strength.|
|Bravera||2||No||No||No||Yes||No||Yes||Strongly increases ally's strength for a shorter amount of time.|
|Faith||2||Yes||Yes||Yes||No||Yes||No||Increases ally's magic.|
|Faithra||2||No||No||No||Yes||No||Yes||Strongly increases ally's magic for a shorter amount of time.|
|Haste||2||Yes||Yes||Yes||No||Yes||Yes||Accelerates the rate at which your ally's ATB gauge refills.|
|Vigilance||2||Yes||Yes||No||Yes||Yes||No||Increases ally's chance of interrupting enemies and not being interrupted themselves.|
|Enfire||2||Yes||Yes||Yes||No||No||No||Adds fire damage to the ally's attacks.|
|Enfrost||2||Yes||Yes||Yes||No||No||No||Adds ice damage to the ally's attacks.|
|Enthunder||2||Yes||Yes||Yes||No||No||No||Adds lightning damage to the ally's attacks.|
|Enwater||2||Yes||Yes||Yes||No||No||No||Adds water damage to the ally's attacks.|
|Protect||2||Yes||Yes||Yes||No||Yes||No||Increases ally's resistance to physical attacks.|
|Protectra||2||No||No||No||Yes||No||Yes||Strongly increases ally's resistance to physical attacks for a shorter amount of time.|
|Shell||2||Yes||Yes||Yes||No||Yes||No||Increases ally's resistance to magical attacks.|
|Shellra||2||No||No||No||Yes||No||Yes||Strongly increases ally's resistance to magical attacks for a shorter amount of time.|
|Barfire||2||No||Yes||Yes||Yes||No||No||Increases an ally's resistance to fire attacks.|
|Barfrost||2||No||Yes||Yes||Yes||No||No||Increases an ally's resistance to ice attacks.|
|Barthunder||2||No||Yes||Yes||Yes||No||No||Increases an ally's resistance to lightning attacks.|
|Barwater||2||No||Yes||Yes||Yes||No||No||Increases an ally's resistance to water attacks.|
|Veil||2||No||No||Yes||Yes||No||Yes||Doubles an ally's resistance to status ailments.|